Ive been contiplating what to do with this build and been reading alot of post. What ive decided is this. Take the '74 400 block bore it.30 over to freshen it up, instead of using the stock heads and intake. Ill be using a tbi intake and heads off of a 350. Instead of the 350 tb ill be pulling a 454 tb, distributor and all wiring from a 454 out the salvage yard. Have the stock crank turned run 5.700 rods with flat top pistons. Tranny will be a 700r4 and rear end will be a 14 bolt gm with disc brakes gear either 3.73 or 3.56 . Now what i wanna ask is what cam and lifters should i run? Plus what do u think the compression will be? Would like to thank you in advance for the help and imputs
First off, a 14 bolt rear end is junk! Find another. Your tranny choice is good but make sure it has a 30 spline input shaft. The 27 spline input shaft 700R4 is junk and won't last or even hold up. Last but not least, you cannot run 5.7 rod on a stock 400 crank without big dollar custom pistons. If you want to run a stock crank you'll need 5.565" rods (stock length). Also be certain that you drill "steam holes" in the heads you're gonna use or you will have temperature issues.
Ok I did not know that ty. I do have the stock gm 12 bolt still in the truck. Also if its possible what size cam would go good with the set up. My buddy keeps telling me energy cam from comp cams. Whatever cam i run ill get the lifters that go along with the set up. What about push rods? Sorry to be asking so much im new to the motor building.
Any SBC head on a 400 block will require steam holes to be drilled. That rear end is overkill... You will not break a 14 bolt GM full floater rear end but you will have an 8 lug pattern out back.
compression depends on the heads cc 76cc flat top will give you 9.2 to 9.5 depending on gasket thickness, wiseco makes reasonably priced pistons you can also get reversed dome if the heads are 64 cc you have to use the damper and flywheel with the 400 crankshaft.
I have to ask..... Is this build on a very tight budget? I never had a problem running the stock 5.565" rods but you will need to stay with an "external" balance which at times can limit you in some aspects. If your budget is a little open look into a "good" rotating assembly. When I say "good" I don't mean something from Scat, I mean something like Eagle. Then you can run a 5.7" rod, piston choices open up and you can go with a "neutral" balance.
I built a 400 with cast flat top pistons with a 5.7 rod and stock crank. Common and cheap pistons and no problems in a street/strip motor.
If i remember right the 350TBI heads are 64cc that will make the compression pretty high with flat tops.Check your heads before you get pistons.I think your 12 bolt should be fine why do you want a 14 bolt rear?
Not really correct. KB sells 5.7 rod hypers, not real cheap, but not what I would call "big dollar" either. http://www.speedwaymotors.com/KB-Chevy-400-Hyperutectic-Pistons-Dish-57-Inch-Rod,24950.html
Well, this is true George and I've used the KB pistons. They're good pistons but they're not cheap pistons and too many shops don't know how to properly clearence them causing them to fail. I have since switched to a better rotating assembly and piston choices & quality greatly expanded for a less (or the same) money.
All awesome responces learning a good bit. My budget is open its not.gonna be ab overnight build. But keep in mind we will be restoring the whole truck As far as the 14 bolt i was wanting to do disk breaks all the way around and my friend just threw that in because the strength of it. But it does have the 8 bolt patern which i dont want. Thought about a ford 9inch as well. Ive been looking in the jegs catalog and summit catalog . Ill be looking for a good rotating assembly. That way i will just have to choose what type of piston
Thanks im going to u pull it soon. Its like a junk yard but u do all the work and its dirt cheap. 700R4 was only 92 bucks. And i believe im gonna save up and get an eagle rotating assembly. Was trying to use as much of the motor as possible to save money.
Sell what you don't use! Some of the un-used parts will still have some value to some people. The money you get, even if it's only a little, can help you buy the parts you'll want. There's already a thread from a member looking for a stock 400 crank. List your old parts in the H.A.M.B. classifieds.
Thats a great idea. I just called the local u-pull-it and i can pick up vortec heads for only 35 a piece. I know the gm 12 bolt is getting harder to find and the one im not gonna use already has 4.10 gears. Now for intake i called the local speed shop and he told me to get the permormer vortec intake instead of using the stock one. And also said the heads are bad about cracking. Whats your thoughts on it
True on both. I'm no expert on Vortec heads 'cause I try to run close to what was around back then. With that said, I'm running World Sportsman heads. No they weren't available in the 60's but they are iron heads that flow much better than a set of 462's and they won't break the bank especially when you can find them used.
I see hundreds of the Vortec heads per year. They run about 70-80 percent crackd. If this is a new build I wouldn't bother with used Vortec heads. They will cost almost as much, in machine work, to get usable as a new set of aftermkts.
Not a big fan myself, but a lot of HAMB guys like 'em, so I figured I'd let him know. There are situations where I would consider the hypers, but I'd make sure and sacrifice a goat under a full moon first.
Well that changes alot. Waddayacare what would the heads your running come in. If the parts place has em i can get em for real reasonable. It may be best just to buy a new set of vortecs and performer intake to run the 454 tb on. Tryin to get the best hp and torque but with good gas mileage. Well decent cas mileage. Once again thanks for yalls imput.
Here, take your pick! http://www.summitracing.com/search/section/cylinder-heads?keyword=world sportsman From 400 on up. Everything depends on everything, from the pistons, to the CC's of the head, to the intake, to the carb, etc. I'm running 5xx horse with a 700R4 and getting about 18 mpg on the street.
Brand new aluminum aftermarket heads will not be much more money than a complete rebuild on cast irons but a huge difference in performance. I ran 5.7 and 6.0 400's dirt tracking years ago and if this is a strickly street motor I would probably go 5.565 rods. If you switch rods be sure to check cam lobe clearance.
Yea its gonna be a street motor. Nothing to out there. Been doin my research on true cast vortec heads from '96-99 . Got the cast numbers and all the specs. Even guys that have done the same build im going to be doing with no major head work pulling out 400+ hp. But gonna continue doing my research on all replies i have gotten and see what best suits my application.
The Jalopy Journal
