600 h.p. is a very unrealistic figure for an n.a. 383. I haven't had mine dyno'd yet, but D.D. estimates mine in the low 460's, and I don't have a mild cam either. My iron heads have been worked over very well also. D.D. estimated a tad over 500 h.p. with AFR aluminum heads. Those computed out to be the best bang for the buck heads for my engine.

 

yeah the engine sat on a stand all coverd up for like 5 years.

 

Given that we know the engine was sitting for a long time plus the evidence of water or whatever causing rust in the cylinder/piston rings plus a historical knowledge of detonation/preignition I would suggest pulling the engine the rest of the way down to inspect the bearings oil pump and such. This way you will know exactly what is there internally.

 

Those pistons don't pull 12+ compression... Unless you've got 58cc heads and had them shaved TREMENDOUSLY.

Comp Ratio: 10.4:1 w/58cc Head, 9.72:1 w/64cc Head

Pre-ignition with a 9.7+ compression? Could be putting low octane in, lean condition, bad timing, etc., etc.

600+ HP on a naturally aspirated 383 doesn't sound right.

Here's a link to where I got the compression data:

http://www.jegs.com/i/Sealed+Power/8...56F30/10002/-1

 

Its a 383 so you need to take into consideration the stroke in the compression calc also a mild cam can lead to a high dynamic compression. He has 64cc heads, we dont know if the blocks been decked or the head gasket thickness to calculate compression though..

 

well im officially pissed off at the guy who sold me the motor. i started to clean all the carbon build up on the pistons and the one that was pitted turned out to be really bad. so i figured since the others were in nice shape i would just replace that one piston. well i take off the oil pan and see a 2 bolt main cap. yes only 2 freakin bolts on the main caps. and to make me even more angry, when i took the rod and piston out, the bearings were horrible. im at a standstill. i need to talk with the guy who i bought that thing from. as far as i know that motor could have had 250 hp. and the cam and lifters arent rollers like he told me. the flat top pistons arent 12:1 dome pistons like he said they were. i wanna just throw the whole thing in the dumpster.

 

I totally understand but don't get like that. Now you can splay the main caps into 4 bolts.

I also did a compression calculator and you could be pushing the compression you said but that's taking it to the lowest gasket and tightest bore gasket and taking a guess at your deck height. So sorry for jumping the gun but I had 350 on my mind even though I know you said 383.

Well, since you have the lower assembly apart do you know if the lower end is forged or cast?

Might as well look towards this as the time to do it the RIGHT way. That way you know personally what's in it and don't have to take the word of the guy you bought it from. I was in the same boat when I bought mine. Went to change the oil pan gasket and rear seal and ended up in a full blown tear down and rebuild. Atleast now I know what the truth is in it and what it can and can't do.

 

If detonation killed the bearings you might want to look at the main bearing caps for evidense of cap walk. A two bolt main is more prone to this when the detonation is severe. I would try to get your money back. If you are serious about big hp numbers go to a dart block by the time you go through all the machining and splaying the caps you will be around $500 away form the dart and not be close to it in strength.

 

http://www.buydart.com/index.php?mai...products_id=41

 

does a 350 have a 3 1/2" stroke? cuz thats what i meaured from the piston at the bottom to the top of the cylinder wall. if so, i guess its not even a 383.