firebirdfreak87

ok I'm building a 350 for my firebird I'm ordering a sealed power rebuild kit from summit with dome pistons I don't wanna bore it I am trying to figure what heads to use that's gonna b the cheapest but get most HP out of it has 822 on it buying comp cam and 4 barrel edelbrock intake and Holley street avenger carb

travis401

iTrader: (1)

you dont bore an engine for power, you bore it to clean up the cylinder walls so you have a fresh smooth surface for the new rings. disassemble the block and take it to a machine shop so they can check it out. theyll tell you if you need to bore it or if you can just give it a good hone and be done. that will determine what pistons you get and needs to be done before you order anything. i would also highly advise you have them hot tank it and install new freeze plugs and cam bearings. with domed pistons youll need a large CC head to keep CR down.

its a HORRIBLE idea to just take a block from somewhere and slap some new parts into it without atleast having it checked out by a professional.

five7kid

iTrader: (14)

Pick the heads first, then pick pistons to match. There shouldn't be any reason to use domed pistons. In fact, they should be avoided if at all possible.

firebirdfreak87

ok I've already honed it and its gettin hot dipped at my uncles shop and I'm using dome pistons to boost the compression because it only has 8.5:1 compression stock and I'm trying to get 9.5:1 to 10:1 I just don't know what heads to get that are stock on a 350 and not vortec I can't afford that

travis401

iTrader: (1)

changing out to flat tops with a smaller 64cc or similar head will net you about 10:1 depending on head gasket. domed pistons with a 76cc head will get you about the same, but domed pistons come with their own set of problems.

firebirdfreak87

http://m.summitracing.com/parts/SUM-SBCKIT1-000/media

will this work?

travis401

iTrader: (1)

if you dont have to bore the cylinders or turn the crank or resize the rods, yes.

travis401

iTrader: (1)

with that kit and a 64cc head, youll be at 9.53:1 CR. thats assuming a standard deck height of 9.025 and a head gasket thickness of .043".

firebirdfreak87

I don't its been looked at and do you think that'll b good for a street car to toy around in

five7kid

iTrader: (14)

Understand I'm not trying to pick on you, but this, too, is backwards. It should be hot tanked first, then honed (I assume you mean breaking the glaze on the cylinder walls - regardless, the hot tanking should come first).

Okay, let's take this one step at a time.

Compression ratio is a function of the total combustion chamber volume at BDC vs. the total combustion chamber volume at TDC. You divide the former by the latter to get the compression ratio. This is affected by the cylinder bore, crank stroke, piston pin height, piston dish/valve relief/dome volume, block deck height, cylinder head gasket bore & compressed thickness (also known as cylinder head gasket volume), and cylinder head combustion chamber volume.

Now, as to "what heads that are stock on a 350", that is an open-ended question. Because there were many different heads that were stock on 350s. Most of them are absolute crap. The 3rd gen 350 heads, with a casting # that ends in "083", are some of the better ones. If the casting # ends in 882 or 624, those are some of the worst, and, as you might guess, some of the most common. Combustion chamber volume for factory 350 heads varied from 64cc to 76cc. With dished pistons and 76cc heads (very common in truck & smog engines), 8:1 CR was very common.

If you haven't bought an intake manifold yet, then why not consider Vortec heads? The 906 and 062 casting #'s came on '96-'99 light truck 350s. As long as you go to the JY and ask for heads for a '97 light truck 350 and don't let the word "Vortec" escape your lips, you should be able to get a pair of these heads for a decent price (as low as $100 is often reported). With the standard going-through, new valve stem seals, and new valve springs, a mild Comp cam, Performer or Performer RPM Vortec intake manifold, and a 650 Holley double pumper carb (don't bother with those Street Avenger carbs - vacuum secondaries aren't a good idea), you'll have a very nice "street car to toy around in".

firebirdfreak87

is that 100 a pair and if I can get them that cheap I'll go with them just new there expensive and I can't afford that what size cam do you suggest and what pistons should I use would that kit work

travis401

iTrader: (1)

picknpull.com has set prices and locations all around the nation. heads are roughly $40 each, no matter what theyre off of. so for about $80 and some luck, you could have a set of vortec heads. vortec heads are 64cc, so theyll work fine with the kit you posted earlier with the flat top pistons.

firebirdfreak87

what HP you think that setup will get

travis401

iTrader: (1)

that all depends on the cam. with bone stock vortec heads, you wanna keep lift under .460"

firebirdfreak87

ok what if I want a higher lift what valve springs should I get and what cam do you prefer

travis401

iTrader: (1)

valve springs would depend on the cam. with vortec heads you dont need a high lift came for them to flow great. id stick with a cam below .460" lift and with a duration of around 230 or under. you can call up comp cams or some other cam manufacturer, give them the specs of what youve got in the engine and what you want out of it and they can advised you on a good cam.

stock L31 (vortec truck engine) were:
Intake lift- .414"
Exhaust Lift- .428"
Intake duration @.050"- 191
Exhaust Duration @ .050" - 196
Lobe Centerline- 111
and that got the engine up to about 200hp and 230 tq with a slightly lower CR than what youll have.

firebirdfreak87

I wanna run 480 lift what valve springs should I use