[crashdawg]

hello every one. im very new here and would like to get some feedback on a 400 build. i recently came across the oppritunity to pick up a pontiac 400 and will be re building this spring for my 1980 trans am.my question is really just looking for oppinions on how each build there 400s.i will be staying mostly stock but we plan on boring the block and a little bigger cam to go with headers and duels. what cam should i be thinking about? like i said i i do want more power but also want to keep it streetable. also my car now has a 301 and i have read that the shaker wont fit when i upgrade to a 400..any thoughts? like i said all info is greatly appretiated.

[Tim Corcoran]

Welcome to the board there are a lot of of experienced people here that can give you good advice but there are differing opinions. One of the first things you need to consider is what heads you are going to use. You should target your compression ratio between 9.0 to 9.5:1 compression and this is usually is accomplished by selecting the right cylinder heads. I also recommend that you have your machinest zero deck your block. Please tell us what heads you plan to use for this combo.

[steve25]

Since you do not need a ton of HP a stock head will serve you well.
A very good head to start off with that is not highly sought after is the late 1974 to eraly 75 5C -4 casting off of a 350 cid motor, this head with a zero deck clearance, .030" over bore and regular replacment 4 valve notch pistons will place you right in the tad above 9 to 1 compression range.
Other heads you could use would be the latter 6X-4,or anyother head off a 71 and up 350.
Any of the other heads though will not have the needed screw in rocker are studs and will have to be converted over, which is not a big deal, just more cost during the rebuilding process.

[Txbobcat]

Before changing heads why dont you list what heads you have on the 400 now and welcome

[A.W.Dille]

You may also need to check the date code on the block as to see ir your present mounts off of your 301 will bolt correctly or not. If it is a 70 and up block you should be fine. You can find the year cast and date code on the back ot the block next to where the distributor sets.

[72LuxuryLeMansLa.]

Originally Posted by crashdawg

hello every one. im very new here and would like to get some feedback on a 400 build. i recently came across the oppritunity to pick up a pontiac 400 and will be re building this spring for my 1980 trans am.my question is really just looking for oppinions on how each build there 400s.i will be staying mostly stock but we plan on boring the block and a little bigger cam to go with headers and duels. what cam should i be thinking about? like i said i i do want more power but also want to keep it streetable. also my car now has a 301 and i have read that the shaker wont fit when i upgrade to a 400..any thoughts? like i said all info is greatly appretiated.

Welcome to PY! If you want to see a bunch of combinations, look at the sticky at the top of the street section where members list their combos. You say you want it "streetable", well with roller cams, light weight rotating assemblies and modern heads (either through porting or aftermarket) guys are running around with 500+HP daily drivers so you will need to give us a budget to work with. As TXBOBCAT stated a good starting point would be to tell us which 400 you have by giving us the casting number/engine code, head casting numbers, transmission and rear gearing.
Most guys are of the opinion that since you need to buy rods and pistons(forged) you may as well spend a few hundred on a cast stroker crank and go with the "no replacement for displacement" philosophy. Again, your budget is important.
You can also go crate from Pdude(member) or another reputable builder such as: http://lenwilliamsautomachine.com/Home.html . Ask for opinions on builders and these guys will provide you with no less than a half dozen choices. Whatever you decide, just take the time and do the research and these guys will educate you.

Good Luck!

[crashdawg]

thanks for all the replys. i guess when posting i wasnt thinking much. i will get the info off of the block and heads and let everyone know. this may actually save me some money. a friend of mine has the 400. he was going to put it in his 79 that he has owned for 25+ years, but he put a 428 in instead.(he has a bigger budget) after i get the numbers i will post. i hate to admit it but the cost of a stroker isnt possible at this time . thanks again

[screamingchief]

Nothing wrong with building a 400 vs. a stroker,but there are a few things to understand.

I advise staying away from the 557 block castings,for more on that just do a search on that deal and decide for yourself.

But more than anything else on a 400 cid pontiac build,piston chocie is what makes/breaks them as the available piston choices are found to contain some serious duds.

Stay away from the 8 valve relief "jobber" cast pistons,they're junk,simple as that.

They just screw up the CR/quench situation in major ways,and to correct for that takes some serious compromises that really should'nt be an issue in the first place.

Even if you zero deck to account for those 8vr cast pistons sitting waaayyy down in the hole (.030" or more typically),you still have to account for the 15-20 cc's from the added valve reliefs & large bevel those pistons typically have.

I'd also stay away from the KB hyper pistons too.

So that mostly leaves aftermarket forged pistons as the only decent 400 cid piston choice.

My preference there leans to the Icon forgings.

There just are'nt any good "budget" piston choices for a 400 pontiac build,not unless you can find/score a set of useable NOS 4 valve relief cast pistons on Ebay or such.

And IMO dont bother with OE cast rods either,for the money you'll spend redoing those and adding good bolts,you'll be ahead in the game with a set of the aftermarket "budget" 5140 I beam rods available thru most any pontiac vendor.

Aside from that,decide what heads,and make sure you target a useable CR via the head CC and piston choice,and cam it accordingly.

With the right piston choice,either the early high compression heads (Icon 14cc dished pistons) or the later smog heads (flat tops @ zero deck) can be made to work properly in a well thought out 400 cid pontiac build.

Cam choices depend largely on rear gearing and the rest of the driveline (4spd/auto),so we really need to know more about that situation to give specific recommendations.

HTH

Bret P.

[John Milner]

One of my favorite 400 combinations is just some flat top trw's, 72cc big valve heads, decent valve springs, 2802 Summit camshaft and some good exhaust. It will make plenty of power for a street car and not kill your budget. You might want around a 3:42 to 3:73 gear with this camshaft though. It will work great with a 4 speed, but might want a little higher stall speed on your torque converter for best performance.

[rexs73gto]

The TRW 4 reliefs pistons are very heavy, even though they are the least expensive of all the pistons , but for my money I like for the cost & weight & the usage of the piston itself I like SRP as they are light have good reliability & cost. Eagle rods are good also. But from there as stated before we will need to know what trans & rear gears you are using or planning to use before we , any of us can give some good info on cam & head choice.