383 Advise

[jay97lt1]

I bought a 383 specs are 4 bolt block 30 over callies 4340 3.75 crank h beam 5.7 rods srp forged pistons mild custom grind cam. stock cast iron heads 9.5 compression engine was being built for a turbo ower lost interrest I paid 600.00 for everything. Engine was never assy. I put it together and installed it. Its just not what I want need more HP.What is the best off the shelf cam I want a rough idle with good streetablity.I am porting a set of stock LT1 heads what is the biggest valve that can be installed in them.

My old 383 had a comp extreme energy 292 sounded badass but didnt make any power .

[popo8]

So you got it together and running and its not enough... or your assuming its not enough....?

[jay97lt1]

running and not enough.

[popo8]

running and not enough.

Well, maybe its not enough because you said the parts were gathered with the intentions of boost.... is the CR low?

[firebird_1995]

So you don't have a turbo on it? If not, a larger cam is not going to give you the increase you want. Going to need to get the compression back up or go fi

2.00" intake 1.56" exhaust valves are the most common size when going larger.

[popo8]

So you don't have a turbo on it? If not, a larger cam is not going to give you the increase you want. Going to need to get the compression back up or go fi

2.00" intake 1.56" exhaust valves are the most common size when going larger.

Exactly where I was heading... put some boost to it... and you will fill all your desires....lol

[jay97lt1]

It will be FI one day and Im getting a set of 97 Z28 heads worked that should up my compression over that cast iron heads thats installed know. My car is a 97 Z28 m6 with 4.30 gears my old 383 would turn 7 grand with no problem this 383 is done at about 5500

[jay97lt1]

Boost is not in my budget right now but it will be getting a good shot of NOS

[popo8]

Boost is not in my budget right now but it will be getting a good shot of NOS

Well then your on the right track getting the CR back up...

N20 likes Higher CR

BOOST likes Lower CR....

As for the cam, I personally am a big believer in L.E. and his custom grinds.... you should contact him... tell him about your build... and he can get something made for you.

[Puck]

When you say "Stock Iron Heads" do you mean just bolted on from another car? What springs are on them? If its been on a dyno yet, does the power just peak early and slowly fall, or drop like a rock at 5500?

Sounds like you are making the same mistake twice like your 292 build that "sounded badass but didn't make any power" and are thinking about what cam to run, when you should be thinking about your heads because thats where the power is. The cylinder head is the most important part of your whole motor and will be the main dictator of how much power a certain cam will make.

[CamaroZGuy]

ditch them cast iron heads, and run a smaller chamber alum head until you want to boost. 9.5 is way too low for a NA LT1

[firebird_1995]

Well if the seller gave you truthful info on what you bought, you got a hell of a deal. I'm thinking you should strongly consider even a used turbo or sc setup. Generally larger cams like more compression ratio and by putting a larger cam in, you'd be going in the wrong direction. As has been said, get a hold of le. He will give you your options.

[Mystery Bird]

Do you know what's in it for pistons, and how deep they are in the hole? You need to work on getting the quench down too. Just throwing a set of aluminum heads on will not necesarily give you all that you want.

[thunderkyss]

When you say "Stock Iron Heads" do you mean just bolted on from another car? What springs are on them? If its been on a dyno yet, does the power just peak early and slowly fall, or drop like a rock at 5500?

Sounds like you are making the same mistake twice like your 292 build that "sounded badass but didn't make any power" and are thinking about what cam to run, when you should be thinking about your heads because thats where the power is. The cylinder head is the most important part of your whole motor and will be the main dictator of how much power a certain cam will make.

Yeah, I think we need to find out what you mean by stock heads. If we're talking cast iron LT1 heads, they should flow more thus produce more power than the '97 Z28 heads he's talking about putting on it.

9.5:1 compression..... That's more than likely going to be the biggest problem. I don't know if there is enough difference in the heads to change that. Swapping the pistons sounds like a lot of work, but may be the best option to produce more power.

[jay97lt1]

the cam is a doug hurbret custom grind with matching springs heads just had a 3 angle valve job. I know im not going to make big power with low compression but I can improve power with a with a higher revving cam and and a good set of worked alm heads decked to get the valves closer to the pistons. I know my current cam will not work with a FI setup falling on its face at 5500 rpm. I am just trying to get a better working setup for when I do go FI. I looked up all part #'s everything is forged in my engine. Thanks for the info.