289 or 351 heads on a 302 advantage?

Ok so im slowly going to start to collect parts to build a 302 bored .30 over to a 306.

I was wondering whats the advantage to putting 351 heads onto a 302?

I already know putting 289 heads onto a 302 give it a higher compression but dont quite know why someone would put 351 heads on.

Any input would be greatly appreciated.

EDIT: I don't really wanna run premium gas. (Just because of prices)

 

I was lucky and got a smoking deal on a pair of 289 Hi-Po heads so I used them on my 302,regular 65-early 68 289 heads will give you the same compression increase as the Hi-Po's but don't have factory screw in studs,but they do use an adjustable stud mount rocker arm which is much better than the later pedestal rockers when adding a performance cam.The only thing is factory Ford cast iron heads do not flow well and are restrictive in the exhaust especially which is why when selecting a camshaft look for one with more exhaust duration and lift than the intake has.On the other hand by the time you pay for machine work and parts to upgrade a stock head you can go this route:http://www.kmjent.com/cart/product.php?productid=4520&cat=17&page=1 and have a lot more H.P. and flow. You might want to order this book also,here is a preview of the cylinder head section and what to look for:http://www.mre-books.com/interchange/interchange5.html

 

351w on a 289/302 will work just fine.
getting the comp ratio correct is where you'll have to do measuring and math.
Also if your planning on the upgrading your
valve size remember the standard 289/302 intake valve relief on the piston is 1.78'.
I went with 1.94/1.60 valves 10.5 cr and 54cc comb chambers. I kinda had a piston valve clearence problem.
All cleared up with a thicker Fel-pro head gasket.
try and check out this book..How to rebuild your small block Ford...it is buy HPbooks
I referred to this book when i looked for blocks and heads to combine..check out page 28. Barnes and Noble has them still.
69-70 C90E-B,D castings 60.4 cc's
1.84/1.54 valves. stock setup. Remember this when using stock valve relief pistons.
I used these heads and had them shaved and didn't need to shave the intake manifold.
but hey each can be a case by case basis.
plus this book has a very detail compression ratio/cylinder head interchange chart.

With bigger valves added 1.94/1.60 and one helluva port job my 306 pumped out 396hp and 398 .lbsTq. It would run 142 mph at Willow springs on the road course after 18 years of life. Turning 7000 rpm with upgraded balancer and aluminum flywheel.
But that was old tech. You can get a run of the mill aluminum head for less that it will cost for machine work these days.

 

the 69-70 351 heads used to be the best, milled .060 they were good. the 289 heads will give you a smaller comb chamber= more comp.,but all the machine work will = the cost of a pretty good set of alum heads, esp if you shop. still want iron heads, go with the late model gt-40 heads. they work well.much better than any of the other factory heads.just my experience.

 

351 heads have bigger ports for better breathng. they were the "secret" upgrade way before all the gt40, trickflow, etc stuff came out. I have a set I will use on a 5.0 block I have for a budget build, once there is a home for it.

 

The World Windsor Jr heads will work better than either of the stock heads for not a lot more $$$ than it will take to do a stock head right. I've put a couple of cars deep into the 12's (at high altitude) on the Jrs. It will take a lot of work and $$$ to get the stock heads to that level. If you use the Jr's you will need a piston with larger valve reliefs, but since you are doing a full build you will need pistons anyway.

 

The pre 1976 351 heads have bigger ports than the 289-302 heads which is why they were a popular swap when we didn't have all the good aftermarket cylinder heads like we do now. 2ton it right, it takes the same, if not or more $$ to get the early 351 heads to come close to what available from the aftermarket now.

 

Heck, even the Explorer GT-40 heads will be a huge improvement over any of the early stock heads unless you spend big dollars on 'em...and then you may as well run aftermarket heads.

If you're dead set on running stock early heads, I'd look for:

69-70 351W heads (biggest ports & bigger valves)
71-74 351W heads (same valves as 69-70 & slightly smaller ports, but bigger than 302)
69-70 302 heads (the ones with the heart-shaped combustion chamber)
Any early 289 heads for the chamber size (but you'll have small ports & valves w/all that CR)

 

correct me if Im wrong but cant you use 351c heads and get the same thing as a 302 boss.

 

Thoughts:

a) If you're prepared to be a little non-traditional: make sure to go roller-cam block.

b) Early 351W heads work fine, were the '70s way to do it.

c) The production Ford "GT40" heads are better (some '90s Explorers, don't recall which years.)

d) Later GT40P heads also good but have oddball plug location/exhaust bolt layout, limited options for headers, etc. (last couple years of 5.0 Explorer production.)

e) Lots of aftermarket choices, Edelbrock, World, AFR, etc. show up on eBay. Don't need really big ones unless you're building a fire-breather, double-check compatibility with factory or desired aftermarket intake/exhaust patterns/port sizes if it matters to you.

f) The 'Clevor' approach (351C heads on a 302/351W block) works well, brownie points for creativity, requires a scattering of uncommon parts which may crimp budget, performance advantage over recent Windsor heads is debatable.

g) Big Galaxie/Falcon has plenty of room for a 351W, find a mid '90s roller block to start with, just sayin' ...

 

The whole sbf head thing is pretty complicated. The exhaust ports are the weak link on all of them. 289-302-351w all have the same size exhaust ports, avoid ones with air injection bosses, they are further restricted. 69-70 351w and gt-40s have bigger intake ports. Early 351w's have bigger valves. The 289 hipo heads have screw in rocker studs that make using an aftermarket cam and valve train a lot easier. They have small combustion chambers that about require premium gas, but give a few horses. The have machined spring pockets that take bigger springs than some castings.

351c heads are not the ticket anymore. Requires special intake, and different pistons for a good compression. The peak horsepower would come at too high an rpm for a heavy car street car with small displacement engine.

In the world of my budget, it would depend what I came across cheap, If you found 289hp or 69-70 351w or gt40 heads they would all be fine. I would look to spend about $200.

The 289 hipos have the advantage of high compression and easy/cheap valvetrain improvements.

gt40s and 351w have better flow.

If you somehow find a grand in your back pocket, get World Products Windsor Junior heads.

 

The guy i got the block from said its a 1968 block. And on the block it says, 34 E7TE S. Someone told me there's some blocks you can't put roller cams in. Anyone know of that?

 

You can put roller cams in anything with a conversion kit. Crane or Comp Cams makes it. I forget which. The cams fit same, it's the roller lifters that need a longer lifter bosses. Someone will chime in with the block casting codes.

 

A 68 block that has a 87 Truck part number?

 

Personnely, I would opt for the cheap and easy to find GT40 Explorer heads. There were 2 different castings, GT40 and GT40P (police).


The mustang forums would be a great place to find out which years Explorer to look for at picknpull.

http://www.allfordmustangs.com/forums/5-0l-tech/76769-explorer-gt40-head-q.html

The best part is that picknpull prices are cheap so a set of very good heads can be yours for under $100

.

 

Yup. For the dollar-down crowd looking for moderate performance, on pump unleaded: GT40, from the Explorer.

 

I recommend going with a mid '90's roller block. They are cheap to find and all the aftermarket suppliers have rebuild/stroker kits on the cheap. As posted above the GT40P heads are easy to find. I bought a mid '90's complete 302 out of an explorer at pull a part for $175. The 302's are out there and cheap to build. I like them better than a SBC.

 

if you run the 351 heads , you need necked head bolts 351 has a different bolt size than 289 302 have to run a different intake 302 289 wont quite fit , also have to run 351 intake gaskets as the ports are a bit different mustangs unlimited in ct carried the head bolts think summit did to , was going to try this years ago ,got some gt40 heads instead

 

I picked up a complete donor truck for parts, specifically for the engine. It was a roller 302 with the Iron GT40 heads and JBA shorty headers. I have heard that there will be header fitment issues with the GT40P heads with regards to spark plug access.

 

around here they used 2brl 351c heads smaller ports made horse power at a lower rpm making it streetable.
I would use the explorer motor

 

I think the biggest problem with 351 heads is the deck hieght difference. You need a 351 intake and header then. I built a 351 and used edlebrock Vic Jr 58cc with 2:05 intake valves. I am very pleased.

 

I put a set of 65 small chambered heads on a 302 with flat tops and it made a mean little engine. It would rap so fast it would make your head spin!

 

If your building an engine for the the car in your sig, I would go with the 351 over the 302. More cubes and torque for the same rebuild cost.
Also, other postings are dead on as to buying new heads over the cost of rebuilding old ones.
If you still want a roller 302, any year 5.0 Explorer engine (for its heads) is a very good starting point. All it needs is a cam change and it will really come alive.

Bill

 

Go the Gt40 (not Gt40P, unless you wanna make your own headers) over the other factory stuff. Try and get a used Weiand Xcellerator too...great combo on a 306.

 

Remember when you start playing with 289/302 and then 5.0's the firing order changes to a 351W and the balance is no longer 28 oz.
1982 and new is 50oz.

A 90 roller block with a set of E7 heads( ported right) and a B- cam will bring a smile to face and shred the hell out of some tires.

I did a .030 over roller block with a stock cam and and ported a set of E7 heads in a 67 mustang vert. Plenty quick enough.

 

Like others have said, you can buy a new or even a used set of aftermarket alum. heads for about the same money as what you'll spend to get the genny cast irons to flow the same numbers. I think you can buy Patriot heads for around 7 bills new.

 

The firing order is based on which cam you run...

 

im going to put some GT40s or 40 Ps on my 302....IF i can find them. seems theyre are always gone from the yard when i get there. if not im gonna get some pre smog ones. for a driver, i always try to stay as stock as possible when it comes to the drive train

 

With any of the stock type Ford heads you are going to get moderate HP gains, and will spend a few bucks freshening them up. IMO, dollar for dollar you can't beat a set of aluminum ones from someone like Edelbrock. If you have a flat tappet cam you can run the E Street heads, and if you have a roller cam motor you can use the Performer RPM heads. You will need roller rockers too, but the heads come setup with rocker studs and are ready to bolt on. The hp gain will be very noticable.

Don