Comp Ratio and New Cam?
Comp Ratio and New Cam? Quick question, I am putting a new custom grind cam in my 383 from Lloyd Elliott in the next month or so. I currently am running 10.5 or 11:1 comp ratio (checking this weeked) and Lloyd said I'd be fine but he wish I had a higher comp ratio. Question is, during the install the AFR heads might have to come off (if the lifters don't come out easily - replacing with LS7 lifters) and if so should I go with a thinner gasket at that time (currently have .041 on there) or mill the heads a little to bump the compression or is it not really worth it? Here are some specs on my motor so you know what I have for the current comp ratio:
383 - bored 4.030
3.75 stroke
SRP flat tops (-5cc)
Deck height/Piston to deck (unknown as it's been 9 years and my builder can't remember)
AFR 190 heads (never been milled)
Felpro 1004 gasket (.041 thick and 4.190 bore)
If a new thinner gasket what would you recc?
Spec on the cam is roughly 230/23? at 108 LSA.
383 - bored 4.030
3.75 stroke
SRP flat tops (-5cc)
Deck height/Piston to deck (unknown as it's been 9 years and my builder can't remember)
AFR 190 heads (never been milled)
Felpro 1004 gasket (.041 thick and 4.190 bore)
If a new thinner gasket what would you recc?
Spec on the cam is roughly 230/23? at 108 LSA.
You should be able to pry out the lifters with a pick of some kind without having to remove the heads. If the heads do come off, a slight mill would hurt anything, expecially if Llyod says he wants your CR to be higher. Only thing is that if you mill your heads, you will have to use different length pushrods and re-verify your valvetrain geometry. Also you may or may not have to mill your intake to seal properly.
You should be able to pry out the lifters with a pick of some kind without having to remove the heads. If the heads do come off, a slight mill would hurt anything, expecially if Llyod says he wants your CR to be higher. Only thing is that if you mill your heads, you will have to use different length pushrods and re-verify your valvetrain geometry. Also you may or may not have to mill your intake to seal properly.
Thanks Lloyd, said I would be fine with my comp ratio now, but said ideally it could be a little higher. I'd prefer to leave the heads on, but if needed then we'll take em off and I will have to at least replace the gasket anyway. FWIW - We're going to measure the PR length anyway as the LS7 lifters have a deeper cup then the LT-1's and Lloyd recc'd checking first as I will prob. need slightly longer PR's anyway. Would it just be better to go with a thinner gasket and not mill the heads as I will be reducing my chamber size correct? If so what gasket would be best?
Taking the heads off will not do anything for getting the lifters out. You have to remove the intake to get the oil pump drive out to change the cam and the lifters are right there.
If you feel the need the pull the heads the first thing to check would be the deck height. Then chamber volume to calculate your actual compression ratio. Depending on your quench distance you may or may not get away with a thinner gasket.
If you feel the need the pull the heads the first thing to check would be the deck height. Then chamber volume to calculate your actual compression ratio. Depending on your quench distance you may or may not get away with a thinner gasket.
Taking the heads off will not do anything for getting the lifters out. You have to remove the intake to get the oil pump drive out to change the cam and the lifters are right there.
If you feel the need the pull the heads the first thing to check would be the deck height. Then chamber volume to calculate your actual compression ratio. Depending on your quench distance you may or may not get away with a thinner gasket.
If you feel the need the pull the heads the first thing to check would be the deck height. Then chamber volume to calculate your actual compression ratio. Depending on your quench distance you may or may not get away with a thinner gasket.
If he's experienced and thinks removing the heads will help him get the lifters out you might wanna rethink where to have the work done. If the lifters are down in the bores all you need to do is spin the cam and they will pop right up. Every revolution of the motor they move up and down so they can't be stuck in there.
