Hey guys well im looking to get some info, a friend of mine is selling me a 383 shortblock that he got assembled and balanced at a local machine shop. He basically told me that he went to the machine shop talked to the guy there about building a 383, got a part list from him, got the parts and got it assembled/balanced. He said he bought a full 383 kit at a local performance shop.

When i questioned him about what parts where used he said he knows it has dished pistons, and the block is an early 90s roller block 4 bolt main. Sometime this weekend im gonna be Visiting the machinist to try to dig out more info. My friend has his own shop and rebuilds 5.3s and 6.0s all day but this is his first 383 attempt so im concerned about the combinations here.

What im mostly worried about is the compression ratio. I want to run on pump gas and detonation isnt fun..

Im also on a tight budget and would like to slap on vortec heads on there or some dart iron eagles. Ive read that vortecs flow better than darts so im kinda sketchy on aftermarket heads. Afr 195s are no where near my budget atm. From the research ive done the iron vortec heads with 64cc chambers will increase compression by a lot with the wrong combo so thats another concern.

Heres the full combo im thinking about.

383 block 4 bolt main
Vortec heads (machined valve guides,screw in studs, comp beehives)
Vortec air gap intake
Lt4 hotcam
Holley 650 carb w/vac secondary (what i have atm on 305 will upgrade down the line)
Gonna run the shorty headers on the car atm with 3" exhaust.

Another concern is the cam choice, the lt4 hotcam seems a bit too small for a 383, so i really need some good suggestions on a cam choice with the combo above, something that will run ok on a stock stall, i do plan on getting one later on but dont really want to add on more expenses.


I know the vortec heads will probably and up creating a lot of torque and decent hp but nothing extreme which is fine for my application, i will be driving the car daily but dont mind the gas guzzling, had v8s all my life. If anything the car will see more stop light jumps than track days. My goal hp is close to 400 but would like the room for improvement down the line.

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So to narrow it down;

1)What would be a good cam choice for the combo above?

2)Will i be able to pull off vortecs On the 383?

3)What modifications should i do to the heads to make it more 383 friendly?

4)What should i ask the machinist about the short block?

5)If i absolutely have to go aftermarket due to compression, whats a good budget head?

6)What hp/torque rating should i expect from this combo? (Im really just shooting for close to 400)

I appreciate any info you guys could give me, i know its a long read but i want to make sure i get things right.

 

Depends on how big the dish is on the pistons. If it's a new shortblock you may be able to see the part number on the pistons and go look it uip. Or you can just cc them on the spot.

For a 383 with 64cc heads tow ork around the mid 9s to 1 compression you need between 15 and 20cc of dish. I think 17/18 was the sweet spot when I was looking into it a while back. Even then, if the CR is too high, just overdo it on the cam to bleed off cylinder pressure if you have to. But I think if it has the right dish range it should be okay.

http://www.empirenet.com/pkelley2/DynamicCR.html

Play with that and find out what you need.

 

Before you buy and heads you really need to know the deck height/piston height (is it 0 decked or in the hole .020-0.025?) and the cc of the dish-i have seen 7cc, 12cc, 15cc and a whopping 22cc dish in a 383 piston. from there you can get a better idea of what you need.

 

Whoever told you Vortec heads flow better than Iron Eagles is full of **** if you're talking about the NEW castings. The old 200cc's are good heads (this is what I've got). They flow much better than a vortec head. You don't need huge heads on a 383 to make power, but you'll choke yourself out with stock vortec heads.

You're limited in your cam choices on a stock converter. Don't go too big or you're going to find out real fast your car drags it's feet horribly. If I were you I'd invest money into a new converter if you're looking for a new cam.. because remember - it's all about the whole package, not just one or two components. Don't forget your gears. If you need to, run what you can to keep costs down until you can afford to do it how you want it. Don't half-*** anything or you'll feel it.

There's a ton of information missing, so nobody can really answer many of those questions. Like mentioned before, deck/piston height as well as head dimensions are a must.