351 Cleveland vs. 351M/400- which is better ?

In other words "There's no substitute for cubic inches" ananymous

 

No reason for you to shut up- message boards are for posting and sharing info- no offense taken if you simply disagree- but I'd like to read valid reasons why. I'll share this with you- a local was running a 351C in the 10's in a Mustang. He kept splitting cylinder walls- and went through 2 or more blocks. He changed to a 351W, runs just as fast, and it's more reliable.

Pontiac issue- the 400 and 455's we built used dished pistons- compression was nearly equal- it wasn't the CR that gave the power increase, it was the CID increase.

I'm a Pontiac guy too, for the last 25 years- my street car has a 455+.060"=470 CID. I run 30 cc dish to get 9:1 and run pump gas. I get a lot more out of the 455/4.21" crank, than I would from the 400/3.75" or 428/4" cranks. If I destroked this engine by 1/2" it would slow way down. I rode in a 400 w/RA V heads- it was not that impressive- actually the 400 was a slug. My 455 would run rings around it.

The fastest cars at the Pontiac meets that run naturally aspirated, run the 455- not the 400. A local here had one in the 8's with iron D-port heads in a tube chassis race car. The fastest Pontiacs now run mid to high 7's in the 1/4 mile, with aftermarket blocks and 500+ CID, in tube chassis race cars weighing around 2200 lb.

Being you're a Pontiac guy, think about this comparison:

400 HO vs. 428 HO- all Pontiac engines- identical bore, same heads, intake, carb, ex. manifolds, rod length, cam but 428 has 1/4" longer stroke-

400-445 ft. lbs.- 360 HP
428-465 ft. lb.s- 390 HP

It's hard to argue with that. Why give up 50 CID, that's all I'm saying.

I don't see the M as being so much more expensive to build than the C- adapt the motor mounts is time more than anything- use the trans or bellhousing that came with the M motor (truck bells for M are quite common, I got one of those for free also) - there are dual plane manifolds available new, open plenum intakes available used- and all the Cleveland intakes fits with spacers- how much are spacers, $200 ? The Cleveland block/crank is going to cost at least that anyway.

IMO the 400M will make more street power than either the 351C or M hands down, esp. at street speeds- with identical top end equipment and cam. In this case, even the rod ratio of 351C and 400M are the same at 1.65- so it's a valid comparison.

The M motors are dirt cheap, sometimes free (we got a free 351M). The vintage Cleveland stuff is the stuff that's actually pricey and getting rare ! The M motor may end up costing less money actually, just more time involved cinching it together.

The 400M being dissed makes no sense to me- it'd be like the Pontiac guys dissing their 455, and opting for the 400 instead. You being a Pontiac guy should know, the 455 makes more power, if equipped the same. It seems like we're in agreement on that to a point- but you're viewing the 400M as being more of a "hassle" over the 351C. That actually used to happen until the 1980's- Pontiac tech books would say the 400 was better- but then everyone started dropping the big-valve 400 heads on the 455 Pontiac- and running faster than the 400's. All the 455 lacked was development.

Much like the 400M...

 

like I said above,i like the big block power i know they will run .thats not realy what I was getting at.doing a 400 ford just doesn't make sence to me because of the $$.you have to go with different heads,pistons,as well as alot more +intake problems.all that adds up to alot of cash for an extra 49 cubes.it's not cost effective.if you have money to throw away(which most of us don't) I just don't think it would be worth it,for most of us.bigger motor doesn't alway mean you are going to be faster than the smaller cube guys.look at how fast some of the 5.0 guy are running.tossing some money at a 400m would make it run passed the cleveland.but tossing the same amount at the 351 C in a different way who would out perform?as for you refering to the cleveland block cracking.i've never had a problem one with the 351C I can't say the same for the M400.maybe it was just my luck.with the reference to the Pontaic stuff.most of the power you get out of a poncho in stock form is in the heads.the 400 pontaic with 6X heads are not going to run as good as a 428 with a set of 13's or 16's.toss some 13's on a 400 and how much more power are you going to make?the 428 will make a bit more but when you pay $1000.00 for a 428 to build and you can get a 400 for $200.00 which is better.the extra cash you save you can put towards an exrta go fast part...but by no means am I saying that if you have a money tree to shake that you shouldn't build a monster motor.if I was rich I would buy one of those 500 + cube pontiacs and it would be a runner and a half but for budget minded people,some times an extra 50 horses is not worth thousand of dollars

 

well, fortunately the M isn't going to cost $1000's more than the C-
I don't see what you're getting at- the M and C motors use the same heads. You can take a C head, and bolt it directly to an M. Also ex. manifolds, cam, timing chain, gasket set, oil pan, lifters, rod bearings, distributor, valve covers, valves- they are virtually identical engines- right down to the head bolts. It doesn't cost that much "more"- there is intakes available for the M, so you really don't even need the spacers. I'm not getting this cost factor you speak of- because in this case, the M is a lot more common and cheaper than the C ! A little hassle and some time maybe, but not excessive cost- we have guys on this board grafting subframes from Firebirds onto 1950's cars- now THAT'S hard. What's so much of a "problem" about bolting on 2 intake spacers if needed, and adapting some motor mounts ? When I built my RA V, I had to build my own headers- THAT was a PITA problem. The intake is a steel welded custom tunnel ram- I had to cut a castiron intake up on a saw, to make a water crossover for it. By comparison, running an M would be a walk in the park for me.

There's nothing mysterious about adapting an engine to a chassis. We put a 455 Pontiac in a 1980 Chevy bucket truck once- the kind they use to service overhead powerlines. Took a bare Pontiac block, added an adapter plate to mate it the Chevy auto trans to the BOP bolt pattern- put Firebird frame and motor mounts on the motor, and dropped it in the truck, bolted it up to the trans and crossmember. Leveled the motor with a carpenter's level across the block decks. Marked/traced the frame where the frame mounts sat with white ink stick- drilled the frame mount holes- in it went like it was born there. The entire mockup took only a few hours. The Ford deal may not quite that easy- but getting the M frame/motor mounts and perches from a truck or car, they could then be adapted into any car with a little time, that's all- not much expense.

again, if you're talking building a C engine a "different way"- well build that M motor that same "way" and it still has a 1/2" longer stroke, so it's bigger, and it will outpower the C by a bit- it boils down to basic engineering- more cubic inches will make more power, bore being the same, on any engine. FWIW, more cylinder head flow will make more power on any engine too, not just a Pontiac.

re: Pontiac comparison- You don't have to spend a $1000 on a 428- you can use any Pontiac block and make one. Just buy the 428 crank. You can drop it into any 455 to make a 428. Another option that was popular as of late- cut down the journals on the 428 crank, and put it in the 3"main 400 block.

IMO 6X heads are not a very good cylinder head for Pontiacs. I flowed a pair, they flow only 210 cfm intake, 165 cfm exhaust. If you want to run a good head on a Pontiac, get the Edelbrock aluminum heads- they flow 290 cfm on the intake, and 200 cfm on the exhaust- more than any D-port head. We've built 2 engines using E-heads, a 428 and 455. The 455 ran 13.40's with 6X heads, then it ran 12.60's at 110 mph with E-heads, no other changes- on pump gas with same intake/carb and headers and cam. So the E-heads heads knocked off 8 tenths- no other changes. The car weighed 4000 lbs. with driver.

You would be buying a lot more than just 50 horses with an aftermarket Pontiac block. The best dyno figures I saw locally from an all-original iron Pontiac 455 w/D-port heads, was 660 HP.

The aftermarket Pontiac 500+ incher with aluminum heads makes 850-1000 HP. So the aftermarket block is worth an additional 350 HP or so, not just 50 HP more.

I can see if you are on a tight budget, and have the trans and top end stuff already to build a 351C- and the car to match it- just building that and not adapting a 400M is a good point. I can also see just running a Pontiac 400 as it is the most common and cheaper, over the 428/455, if on a budget. But not everyone wants the cheapest, easiest way out. We can't judge a motor design based on whether we own it at the time or not. That doesn't make it better- just more convenient. Remember, some wise rodder once said "speed costs money, how fast you wanna go ??" The thread is comparing the M and C engines output- not how easy or cheap it can be put in something- the M has it over the C by 50 cubes- there's no way around that. Hot rodding is not a cheap hobby- and not easy either. That's the nature of the hobby, a lot of it is fabrication. Fab is also a lot of the fun. Anyone can bolt parts together that already fit. IMO, one would be foolish not to take 50 more CID of the M over the C. I'm comparing the 2 engines' output potential and engineering parameters. It's not that much harder or more expensive to use an M over a C motor.

ps- I like that signature- good one !

 

http://www.edelbrock.com/automotive_new/mc/heads/ford_sb_clev.shtml

As I recall from my First car a 71 Mach 1 mustang the biggest problem was a severe lack of go fast goodies and the price to play was much more than a similarly equipped SBC. Mine had a Holley dominator manifold and of course you can now get aluminum heads from edebrock that out flow anything iron from back in the day. They should fit on the 351M, if not the 400 with some spacers for the intake. the beauty of the spacers if made from the correct material would be engine temperature Isolation which theoretically could aid in cooling the intake charge, allowing for even more compression.

 

Additional Performance Enhancing Products for your Cleveland: #7564 Ford 351C RPM Air-Gap Intake Manifold for use on Edelbrock heads #61629, factory Ford 2V heads and 4V heads (with port matching)

 

One major hurdle for the 351M/400 enignes is, at least last time I looked (its been a couple years since I last put together a C) is there are NO off-the-shelf performance pistons available, just stock replacements.

The 351M/late-400 head is NOT the same as the 351C-2V head; it has a casting date from somewhere in the mid-70s. They have an enormous water jacket in the exhaust port that can not be cut out at all, the port is absolute junk on these heads.

The 351C exhaust port is positioned in such a way that in a car with shock towers, header routing is bad enough how it is (it's a royal bitch to get headers in and out, and I was running the engines in a big damn 72 Mach 1); the extra inch of deck height would make it a holy nightmare.

The Performer is the only dual plane that is available for the 351M/400, which is just a aluminum version of the stocker (same goes for the C manifold), no better. The Street Dominator was a sorry manifold, and I think they only made a Strip Dominator, which is a great manifold, for the C.

A 400 wouldn't be a bad motor, but the M is just a de-stroked 400. It has all the disadvantages of the 400 vs. the 351C, plus the reduced CID. No benefit at all to a 351M, other than a good block to put a 400 crank into. A 400 with 4V heads, a good cam, and an adapted 351C intake (the 351M/400 intakes available are really just junk) would be a good runner, if I could have ever found one with the small block bellhousing I woulda jumped on it.

The 4V head isn't too much head for a properly laid out setup in a 351 CID motor... I've had both and would take a 4V head over the 2V any day. The Aussie heads are nice, but they have REALLY small chambers and don't flow as much as the 2V-US heads. The Edelbrock head doesn't flow as much as the 4V, if you were sinking the money into aluminum heads I'd pass on the E-brocks and look into one of the Aussie aluminum heads available, THEY are the big performers.

For the money you would sink into getting custom pistons made, intake spacers, fitting headers, fitting motor mounts, the amount of HP you'd LOSE to a C6, etc... You could get a 408 stroker for a C, have the smaller, rev-happier mains and go.

 

good info from someone who's toyed with them- that's what I'm looking for- thanks

just a few issues...

I don't consider the Holley Street Dominator for any engine a sorry intake- I've seen cars run in the 9's in the 1/4 with that intake design- how bad can it be ? It's an open plenum high rpm design, with somewhat smaller volume than a Strip Dominator. And it can be ported.

There is another open plenum intake called the Edelbrock Streetmaster that was specifically made for the 351/400

Weiand and Edelbrock both make dual plane intakes for the M engines today.

I don't see pistons as a problem- I've put longer connecting rods in engines before, a simple call to Venolia- tell them the rod length and stroke being used, and block type and the ring widths to use- and they make 8 pistons in jiff time. Upon installation first hole, the pistons fit the block at zero deck height.

Header clearance in cars with shock towers- now that IS an issue- I saw a 302 Ford SB in an early Comet- the header bolts were already against the shock towers. At the same time, I know another guy who put a 351C in a early 1970's Maverick, and he also had header clearance problems- the tubes hitting the tie rod ends and steering linkage- and now has to go to a Mustang II front clip to get it to work- so it's not only an M issue, it's a C issue as well- depending on the car it's swapped into.

Mount and clearance issues aside (they can be solved, like with any engine swap, that's part of the job)- I still believe the 400M is just as good and better than the 351C. 50 cubes is nothing to sneeze at.

We also flowed a pair of "smog" 351M heads, after putting Cleveland valves in them- the Ford heads flow more than any standard big-valve 400/455 Pontiac head (including the round port heads), and more than any small block Chevy iron head ever made. With the Pontiac engine rated at 360-390 HP in stock form- and the SBC known for it's stronger 350-375 HP factory versions- it's obvious the M engines have a lot of hidden horsepower in them, that was not tapped into by the factory due to emissions laws at the time. The airflow is there in the M heads even with 2V version. A mild buildup on an M will easily give 350-400 HP on pump gas, for a daily driver.

 

other M intakes

Streetmaster open plenum-see pics

Weiand dual plane- on the Holley website as a "small block Ford" intake, but actually for a 351M/400- 2nd intake down on the list- part number 8010

http://www.holley.com/types/Ford_Small_Block_Manifolds.asp

http://www.holley.com/8010.asp

 

pic- Weiand M intake

 

can't believe the post is still going.lol.biuld the m400 and let us know what you run.no ones trying to knock you from building what you want.by all meens do it prove us wrong.it's funny you was talking about the m400 being cheaper to find than a 351C but you said you was using the heads and other things from the Cleveland to put on the M400.if that the case you will buy the Cleveland and the M400.I have fooled around with both engines,never got that radical on the m400 but from what I've seen the M400 is just not worth the effort.I just don't think you are looking at the totle price of doing the machine work and the parts to put it together.no , I don't want you to think I'm a cheap skate I spend more on machine work and custom parts that I care too.If you are going to spend a far amount of money and you want the bigger motor why not go with the 460?

 

there's nothing to prove- a bigger engine makes more HP- seems that's been proven before many times over, about 100+ years ago ?

 

If the 351M heads you flowed got good numbers, they definitely weren't what I am calling the 351M/400 smog head. It was like a D5 or a D6 casting number (I used to know what it was, but that data has since been replaced in the ol' noggin), and in no way shape or form could ever have good exhaust flow because of the god-awful water jacket around the valve that can't be cut down at all. The early 400 heads WERE 351C-2V heads, but the later smog models were junk with no solution other than replacement. Then again I like 4V heads better anyhow, I've had all 3 popular heads (2V-US, 4V, and Aussie-302C) and the 4V was the best.

I've not had any experience with the Street Dominator for any application other than the 351C, and that particular make and application was junk... Single plane with stupidly small ports and low plenum volume to knock its power band down to streetable levels, but it falls short. They pop up on EBay from time to time and usually go for less than $100 due to their lack of desirability. The best intake I ever had was a Shelby 351D (same as the Blue Thunder) for 4Vs. I was always disappointed with the selections available for 2V heads, nothing really spectacular. The Performer is just a blah-blah stock replacement, and the XCEL-erator was just never very impressive. The 4V options are alot better.

Honestly if you're going to the expense to have custom pistons made, it ceases to be a cheap setup IMO, I'd just toss a stroker crank in a C and be done with it, again for the smaller, rev-ier mains and the small block bell pattern. If I was going to build something with 3" mains I'd build a 351W and enjoy the massive aftermarket support.

 

The heads were a factory 351M head, that we put large Cleveland 2.19/1.73 valves in. That's all you have to do to get good flow for a street car. They were the 2V heads, with the smaller ports.

This just in- add this to the 400M arsenal- CHI now makes a complete intake and spacers for the 400M

They also make aluminum version of the 4V heads.

Now we're cookin' with gas- bolt on goodies for the 400M- watch out !

http://www.chiheads.com/news_400m_cleveland_adaptor_kit.php

http://www.chiheads.com/news_true_alloy_4v_factory_style_cleveland_cylinder_heads.php

this same type of stuff from CHI just won the PHR Engine Masters Challenge on the dyno

see it here:

http://www.popularhotrodding.com/enginemasters/challenge/2006/0610em_2006_challenge_results/

http://www.popularhotrodding.com/enginemasters/challenge/2006/0610em_challenge_results_friday/

The CHI headed 351W "Clevor" (canted valve C-style heads on a 351W block) barely beat Hause's Pontiac though. The Poncho was stronger on the top end, and fluttered on the last pull at low rpm.

 

There's a great article, in the latest Hot Rod mag, on the 400M.

 

500 HP using chevy rods, Edelbrock 351C aluminum heads. 340 dodge pistons with a .40 over bore. and 2 1" spacers on a lowly edelbrock performer intake.

Take that nay sayers.

Of course teht same Hotrod issue pulls two stinkers when it advertises flat black paint at $42 a gallon so "it won't fade like primer" and then they had a 70's mack truck with red rims and wide whites in flat black in the readers rides area near the back.

Sorry I hate when things get trendy.

 

an old Holley engineer did an interview on Youtube, discussed 4v vs 2v Cleveland heads
the 2v heads were 5 seconds faster on the Daytona track

https://www.youtube.com/clip/UgkxAr1ifJF8DZOF6_sq2INCmf6zCyTV7cEd

 

Just to clear things up or muddy the waters, I worked I Ford dealers when the 351M/400 were introduced. There never was a 400M. I still have the introductory book Ford sent out to all the mechanics working heavy line. The 351M is called that because it is a 400 MODIFIED to a shorter stroke to create 351 cubic inches. They are both tall deck versions of the Cleveland blocks, but born in the time of heavy smog requirements. The biggest single thing that will help either one perform is to install an early 400 timing set that returns the cam timing to straight up. As far as transmissions go, the 351M often got the miserable FMX. Both were underpowered from the factory but met smog laws. I owned a 78 Ranchero GT with a 400, that ran respectably, no real power house, but had terrible time passing gas stations. I got 12 mpg, loaded, unloaded, around town, or 80 mph on a trip I made in late 78, from San Diego to Salt Lake City and back. The mileage varied from a "thrifty" 12.1, down to a terrible 11.8. I was a service manager during the dreaded M 40 program in the late 70s when both the 351M and 400 developed horizontal cracks in the lifter valley, just above the lifter bores. Lots of blocks changed out because of that! Breathing was their number one problem. That can be cured with Cleveland parts, aluminum aftermarket manifolds, and careful cam selection. Since the M 40 program got rid of the poorly cast blocks, I would not hesitate to own one again, if I didn't already own way too many cars as is.