Stock heads on a 383?
07-01-2004, 11:05 AM
#1
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Stock heads on a 383?
I know this isn't the ideal way to go, but will I have issues running a 383 on stock heads/ehaust and the HOT cam or even a stock cam?
The reason is that I have to rebuild the motor now, but don't have the money to do the heads or the ehaust how I want. So the heads may have to wait another year or so. So would it be better to build up the bottom to a buget 383, a buget 355, or just keep it stock?
The reason is that I have to rebuild the motor now, but don't have the money to do the heads or the ehaust how I want. So the heads may have to wait another year or so. So would it be better to build up the bottom to a buget 383, a buget 355, or just keep it stock?
07-01-2004, 11:53 AM
#2
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I ran stock heads on my 383 with a smaller cam (Comp CC502, 218/224 duration). I had a lot of problems...it blew up twice (hypereutectic pistons + stupid high compression ratios = bad), never ran right when it was running, just gave me all kinds of grief. It dynoed 329 RWHP and 382 RWTQ through a 4L60E and ran a best of 12.60 @ 108.91. This time around, I'm going with forged pistons and rods, taking it out to 385 CI (0.040" over to clean the bores), going with a much larger cam, and having the heads done (ported/polished, larger valves, etc). Hopefully this time it will stay together.
On the other hand...there was another guy locally that had a 383, with a hot cam, and mild heads (barely ported). His car always ran fine. So, I guess it all depends...it may work, it may not. My mistake was not calculating dynamic compression...it ended up being way more than it should have been to run on pump gas. Had I stuck with the larger cam I had in there originally, I don't think it would have blown up.
I don't know if that helps any or not. I guess I'm trying to say that it will work so long as you run the numbers and do everything right, but don't expect a huge HP increase if you use a small cam and stock heads. I would recommend at least buying a set of headers and a y-pipe...look into the Pacesetter longtubes since they're fairly cheap. I severely doubt your 383 would run worth a crap with stock manifolds.
On the other hand...there was another guy locally that had a 383, with a hot cam, and mild heads (barely ported). His car always ran fine. So, I guess it all depends...it may work, it may not. My mistake was not calculating dynamic compression...it ended up being way more than it should have been to run on pump gas. Had I stuck with the larger cam I had in there originally, I don't think it would have blown up.
I don't know if that helps any or not. I guess I'm trying to say that it will work so long as you run the numbers and do everything right, but don't expect a huge HP increase if you use a small cam and stock heads. I would recommend at least buying a set of headers and a y-pipe...look into the Pacesetter longtubes since they're fairly cheap. I severely doubt your 383 would run worth a crap with stock manifolds.
07-01-2004, 10:16 PM
#6
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Originally posted by AndyB
I'm running stock LT4s (except valve springs) on my 383. Works fine and makes a decent amount of power
I'm running stock LT4s (except valve springs) on my 383. Works fine and makes a decent amount of power
Thanks
07-01-2004, 11:27 PM
#7
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.
why rebuild it and leave something to be desired that could have been done the first time? Yes to the headers. A 383 with stock manifolds is kinda waste of building a 383 in my opinion. Save some more $$ and do it all. Cut out the unnecessary stuff also. Key to good motor=strong bottom end & a good flowing upper end. Power is made in the heads/intake then you have the bottom end strong to withstand it. That is what I have learned from building motors in the past.
just my $.02
just my $.02
07-01-2004, 11:35 PM
#8
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I'd do the 383, the cost difference in very minimal when you compare an aftermarket 3.48" stroke crank to a 3.75" stroke crank. The only real cost difference is in the machine work to the block.
The motor won't make its full power using unported stock heads, but it should make more low speed grunt which will be nice for driving around. It'll probably wheeze like an old geezer if you try to run it past 5k rpm cause the heads will be a bottle neck. If you're going to do the heads in a year, then go ahead and build a nice bottom end and swap the heads when you can.
The motor won't make its full power using unported stock heads, but it should make more low speed grunt which will be nice for driving around. It'll probably wheeze like an old geezer if you try to run it past 5k rpm cause the heads will be a bottle neck. If you're going to do the heads in a year, then go ahead and build a nice bottom end and swap the heads when you can.
07-01-2004, 11:38 PM
#9
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I say go for it. I mean, not to sound like a dick, but from a 350 to 383 is only a 33 CI difference, Big but not huge ... 33/8=4.125 ... Im sure stock heads can feed another 4.125 inches per cylinder until you get the cash to build it rite. LT1 heads are NOT the most restrictive V* heads in the world. Look at some truck engines ... a ford 460, 230 HP ... Granted its not made to be a Hi Po engine, but my point is, It wont HURT the car to run it on stock heads as long as you make sure your Comp. Ratio is appropriate ... If you need the car now, do it. If you have another car to drive. Wait until you have the money, or take a personal loan, borrow it off of someone , whatever, do what you have to do if you need it, but if not wait and do it rite once ...
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