383 or 400?

In a bass-ackwards way, that is sorta what I was getting at- the OP's heads get "better" the smaller the engine is...


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max RPM is at 5500, meaning the peak needs to be at 5000 RPM. So that 20hp gain you see at 6000 RPM really is misunderstood. Also, those are stock flow numbers, I did recomend doing a valve job and port work to improve low/mid range flow. Instead of chasing after 20hp you need to think in terms of 20ftlb at 3000 RPM, it changes things a bit. His cam will most likely not even be at .500" lift.

Since the heads have already been redone the valve job is probably a no go, but he can still disassemble them and do some port work. Going Vortec would gain him a little bit, but the cost to get there is far too high and that money could be better spent on a better carb, exhaust, rings, etc.

Part of these "this is what I have, what can I get" posts is using what they have- in most cases because of a budget.

Anytime the redline is set at 5500 RPM its not about power but midrange torque.

A very good idea
Done.
Str8lnr- No duplicate threads please.

Mikey

__________________
my signature lines...not really directed at anyone in particular..

BE different....ACT normal.

No one is completely useless..They can always be used as a bad example

I'm a big 400 fan, and normally I would say build the 400, but you are putting this engine into a Muckstang. I don't want to see a good large cube CHEVY small block WASTED on a cross-breed . Cross-breeders should be slapped silly unless this is old vintage tin and the swap is interesting, early Cad, Hemi, Nailhead etc.

This goes for all you guys putting SBC's in your street rods too.

Sorry for the rant, but you picked a brand when you picked the body, the engine brand should match IMO.

X2

but if you still go with it, do the 400, since the 350 is already bored, sell it to help pay for the machine work on the 400, if you want forged why not go with a stroked crank as well, i have always wanted to build a 400@ .030 with a 3.875 crank (421) i dont think you have to clearence to much and i know if you add much more stroke it is advised to run an aftermarket block, but im pretty sure you can get away with the 421ci, your heads "stink" for a 400 humps are just fine for a mild hotroddin' 350 only looking to put out 300-400hp but if this is a track car i would hope your trying for 550hp, it would be easier with the 421, i wouldn't use a head with lower than 215cc runners and 2.05 int valves (you said track only right) you could easliy get away with 230+ and 2.08's, i'm a fan of iron heads and you can get all this still with iron for about 1000, or you can go the alm route but you'll spend 1500+ (if so AFR's are awsome) someone said before to use hyper pistons, and i dont have anything against that unless you plan on running anyting more than maybe a 150 shot one day, good luck, go with the 400, i still hope one day i get to build my stroker 400

Sorry Cobalt, but if you build the engines the EXACT same except for piston diameter of course- the 400 will always out perform the 383 below 5500 RPM NA.

Now when you start talking about spinning them up around and past 7,000 RPM there are other factors that come into play, but even then 99% of the time a 400 will win, the 1% being to the fact that most 350's are more rigid than 400's and have better ring seal which can add up to a lot in race applications.

As far as the hood ornament matching the valve covers... I used to think that way too, and for the most part stay that way with my cars, but even GM swaps buicks in caddy's, pontiac's in chevys, chevys in everything, olds in caddys, etc. Hell Jeep put AMC, mopar, chevy, (and maybe ford but not sure about that one) enignes in their wranglers.

well i took the 400 block to the machine shop today so that the one im going with, and for the guys talking about staying tru to the brand this is a dragcar they runed hemis in everthing back in the day, but i also have a dd mustang lx thats chevy powered built ford tough with chevy stuff thats my moto lol, but back on the subject i took the 400 block to the machine shop and the guy said it checked out visually so i left it, itll be about a week before he can even touch it so where gonna work out the details once the block is proved healthy we know its gotta go .030 over due to a broke ring. the heads have been shaved .010 to clean up they where rebuilt with performance in mind but for a much smaller motor but i think theyll be alright after alittle pocket porting i mean if i was cranking 6500 rpm id problably get a different head but im not so i think it will be alright , as for the track it will mostly be 1/8 but there an old 330ft track around here that i love so ill be spending alot of time there too but thanks for the info and keep it coming now that youve talk me into the 400 what should i do to it

You are forgiven, my son.

BTW- what part of:

"If it were me, I would build a 383," Am I supposed to check w/you first? LOL

and

"First, you build the 383 with “claimer” parts- budget means a lot in this circumstance, but not at the expense of reasonable durability and performance.

Then, you talk the engine up (stroker, fulie, torque that rotates the world beneath your tires, awesome top end charge, great MPG, even- that is, if you can keep a straight face); give it “street cred” and a Bad-A rep.

Then, foist it off upon that one deserving dude. You know the one: big-mouth, know-it-all professional student with all daddy's money but no street-smarts.

Take that scroat’s money, put it into a tough bottom end and a killer set of heads for the 400 and never look back! Ha."

did you not understand?