PhLaXuS

OK...money firbids it now, but when I go to build my 383, I was going to build the short block all in a few days and then put the old 350 heads on to keep everything from rusting. My question is:

If I build a standard straight-forward-type 383 where I grab a 350, bore it out, put new crank/rods in, etc. can I actually run the engine with the old 350 heads & intake? I know it would ru nlike total CRAP, but would it run at least comparable (if not better) to a really out of tune V6? I know I'm delving into a lot of specialized questions such as head casting displacement/detonation and the like, but assuming no detonation, do you guys think it could run? This would be cool if so because I could build the short block and drop it in with a new transmission while saving the money for new heads/induction.

Sonix

iTrader: (1)

You want to build a 383 to outrun an out of tune V-6?
I think you will be pleasantly surprised.



It'll run ok, just remember your heads are what make the power, so the sooner you replace those, the sooner you'll be even happier...

Streetiron85

What's the casting # of the heads you were intending to use?

A 383 short block with flat top pistons can be built. You can use 76cc factory heads then upgrade later to a more HP head/intake setup when $$ allows. It'll have in the neighborhood of 9.5:1 CR and it'll be pretty powerful, but not as powerful as with some good heads.

That's one approach anyhow.

PhLaXuS

That's what I was hoping! I didn't do the math (I thought asking you guys would be better than doing the math as this type of thing is sometimes more experiential than mathematical.). I knew that the engine would be severely choked with the 350 intake & heads and would seem a bit off/not run too great, but I was really hoping that it would be possible to build this engine in stages. It also will give me a better understanding of PCM tuning. I likes...

Don't have the engine (or casting number) yet. I was going to grab a 350 TPI from a local salvage yard and go from there. Does anyone have a clue how much power a 383 running flat-top pistons would make @ ~4000 RPM assuming 350ci TPI intake & heads from something like a late 80's Z?

Sonix

iTrader: (1)

You're going with TPI? whoa, you're brave.
Well if you enjoy tuning PCM features.... You'll have a blast!

Streetiron85

If you were planning on getting some scrapyard L98 heads, the compression would probably be too high for a 383 with flattops.
IMO it's a smarter plan to begin with a set of smogger heads and some flattops, in anticipation of upgrading to some aftermarket heads that tailor your CR to the rest of your engine combo, and your car.

I think it's better to upgrade from low comp factory heads to higher comp aftermarket heads, than it is to run an engine that pings with 11:1+ CR factory iron heads.
Not everyone agrees with that though.

PhLaXuS

Chance plays a part in this as the base 350 I'll be running with will be kinda up to whatever I like out in the yard. Most of the engines that I find are V6's, but maybe 2 - 4 times a month I'll run across a 350. I'm planning on running water injection and keeping the knock sensor in the loop. I already run 93 octane exclusively as my current L03 really seems to like it. If it comes down to it, I'd retard base timing enough to kill detonation. The plan is to build a short block for a continuous 700HP & it would really suck to screw my engine from something as simple & preventable as detonation. If the heads that come with the 350 didn't work, I could just wait around for some better stock irons from the yard. That's the beauty of forums such as this: we can knock around ideas before beginning.