Hi im in the process of building a 350 for my car. Here is the list of what I would like to use any idea how much power it should make and is there anything I should change?

bottom end - stock rebuilt 1975 350 2bolt mains

heads - AFR 195s with 1.6 roller rockers (should I go with 64 or 75cc?)

cam - comp cams etreme energy 274

intake - proffesional products crosswind intake (same as airgap rpm)

carb - 650 speed demon carb mechanical secondary (my car is an auto will this be a problem?)

would using a holley stealth ram instead of the crosswind and demon offer me more torque and hp?

 

No, I don't think the stealth ram would increase the HP. It'd give you better mileage and be a bit smoother on the powerband. Is it worth it to you? Price out the FULL injected setup, including everything you need to make it work right, then decide.

If you stick to carbed, do some port cleanup on the crosswind. I've heard the casting quality can be... Sub-par. Grab some single cut carbide burrs and sanding drums and an intake gasket and port match it. Go as far into the ports as you can reach.

You'll want 64cc heads, especially with a stock 350 (12cc dished pistons, .045" deck height?). I suggest you re-think the bottom end. I'd mill the block decks at a very minimum, zero deck it. Then with 64cc heads you should be good as far as compression goes.

 

Hmm... why would you recomend decking? I was kinda hoping to keep the bottom end as is until I had the money to build a nice 383 for my future blower setup. What would my compression be approximatly with stock pistons and stock deck height? Would stock TPI pistons be a better choice? I have a brand new set of those in the basement.

 

ditto on 64cc's. That will help your compression but does depend on the piston specs you have in that rebuild, and the deck height of the block. if its a stock 9.025" deck and a 9 inch rotating assembly, then your .025 in the hole. i'd suggest a .028" gasket by mr gasket to keep quench down to a somewhat acceptable level. depending on the pistons you should be somewhere in the 9's to 1. A bit low but workable

 

Maybe sombody could recomend a good set of pistons that wont cost me too much? I would like to stay in the 9 and a half to 10 and a half compression range for pump gas.

 

any of the hypereutic pistons will work if you are looking to make less than 500 hp or are not spraying more than a 100shot of nitrous.

Keith Black, Speed Pro, TRW, etc make decent cast pistons for under 300 a set.

with 64cc and a quench of around .040", look to get a flat top piston with 5cc valve reliefs and no more.

I'd zero deck the block so your pistons are not in the hole but flush, so you can run a standard .039-.040 thick gasket and with a -5cc to -7cc flat top piston, you will be around 10.0 to 10.3 to 1.

without zero decking and keeping .025 in the hole, run a thinner gasket like the felpro coated .015 or mr gasket .028" thickness. with the .028" and a 5-7cc flat top piston, you will be around 9.8-10 to 1. Thats where you want to be.

 

cool now another question since these are aluminum heads should I be looking more at 10.5-11.5 compression for power on pump gas and if so how could I get there?

 

All I have to say about carbs is AED! Get your flow numbers from your heads, figure out what cam you are going to use and call them....you wont be dissappointed.

 

No, with your AL heads shoot for 10-10.5:1. 11:1 is too high to safely run pump gas unless you're careful about ALL the details. Don't trust people who say you can run 11.5:1 on AL heads with "no problems". Just because they did, doesn't make it "safe" or "reliable".

Rebuilder pistons drop the deck height an extra .020". Without decking the block you're at .045" deck height, any head gasket in the world will throw your quench right out the window.

Buy speed pro hyper pistons that are $100. H345's IIRC. Get the block zero decked, run a .040" gasket like Orr89 mentioned. With 64cc heads that's just barely over 10:1 (ask me how I know this exact number eh?). With the XE274 it'll run like a champ.

 

Thank you sonix. I checked out the pistons on Jegs and it looks like the speed pro 844-345npstd will give me about 10.2 compression without decking is this right?

 

Anybody?

 

No, not really...

Those pistons are among the ones that are an extra .020" lower than stock, which are already around .025" below the deck; or, about .045" total "down in the hole" at TDC.

With 64cc heads, .039" head gasket (FelPro 1004 for example), 6cc valve reliefs, and .045" deck clearance: 9.2:1. Same except .025" deck clearance: 9.6:1. And, same except zero-decked: 10.2:1.

You'll DEFINITELY need to have your block decked, to use those pistons.

 

sonix is right and wrong.. i'm running 11.1:1 on 92 octane with literally NO PROBLEMS.. but to get it to be happy, you will need a rather large cam duration to bleed off compression on the low rpms which takes from your off-idle power.. you must also highly consider a port/polish on the combustion chambers to relieve any casting flash that could spark up detonation.. quench distance is also a big deal since, anything over 0.050" is getting too large and encourages detonation.. but then again, cam duration can help.. i used to run 10.65:1 with a .065" quench and it ran very well on pumpgas.. the times in my sig are with that combo.. people would say, its unsafe to run it how i did but i was fine, due to all the prep work i did..

 

Then i'm 100% right. If he threw in 58cc 416 heads, as stock, with his .045" deck height and .040" gasket, stock plugs, 91 octane at sea level with a comp262 cam - it'd ping all the way down the street. That 11:1 (or thereabouts) isn't the same as "your" 11:1, or Joe's/Steve/Mike/Jim-bob's etc etc.

The cam, quench distance, head style, head material, CAM!! elevation and all the other little details make it possible. It's very dangerous to suggest to someone that because you (or whoever) ran 11:1 with no problems, then someone else can.

Anyway, a zero decked block with H345's, .040" gasket, 64cc heads (such as AFR's) and a compxe274h is a very common, very good setup. As sofa mentioned, a hair over 10:1 CR. That's got most of the details covered right there.

 

how are you getting a deck height of .045"? arent most small blocks standard deck height at 9.025"? Most pistons for 350's have 1.56 compression height and with a 5.7 rod and 3.48 stroke, thats 9 inchs of rotating assembly to put the pistons in the hole about .025"

 

Speed pro pistons have a 1.54" compression height. Most replacement ones do, aside from the high end ones, SRP, wiseco etc

 

sonix, i'm just saying you can run 11:1+ but it will need a good combo to be healthy on pumpgas.. and this guy said he's gonna run afr 195's..

i'm not pushing the topic.. i'm just saying you dont have to ignore it..

to be honest, i wish i went solid roller and AFR's from the start.. then i could have been in or near the 10's a long time ago.. but i'll just try with what i got.. solid flat and restrictive brodix..

 

Ok so it looks like its back to the machine shop lol to spend another $180 to have the block decked thank you guys