I have an auto/Lb9. I am getting an LT1 intake and so the RPM range will be raised. Now my questions are about that added rpm range.
1) What springs should I get to put on my heads, and I might home port them a bit as well. Nothing major, just smoothing things out.
2) What should I change my shift points to? I will dyno this intake obviously, but anyone care to guess where max hp will be?
3) If the L98 cam is a tad tamer than the Lt1, how does it run out of steam then? I was under the impression that the TPI was the culprit. I guess I need some lessons in cam lobe & separation & duration.
Thanks,
-Kevin
1) What springs should I get to put on my heads, and I might home port them a bit as well. Nothing major, just smoothing things out.
2) What should I change my shift points to? I will dyno this intake obviously, but anyone care to guess where max hp will be?
3) If the L98 cam is a tad tamer than the Lt1, how does it run out of steam then? I was under the impression that the TPI was the culprit. I guess I need some lessons in cam lobe & separation & duration.
Thanks,
-Kevin
Supreme Member
well.. what kind of cam are you going to use? what rocker ratio?
the TPI is the "culprit" for the lower RPM range..
hell, even if you went to an LT1 intake, LT1 cam and stayed with 1.5 rockers, you'd be way better than the TPI
i personally am doing the LT1 intake, LT4 Hot Cam, with 1.5 RR
BUT.. the limiting factor will then change to heads.. the L98's will not flow what i need them to flow in order to take advantage of this set up.
so are you doing this on your 305??? a few people have done it.. not sure what heads they used, but you really need to open up your stock heads to see good gains.
hope this helps.. some one else might want to chime in here..
the TPI is the "culprit" for the lower RPM range..
hell, even if you went to an LT1 intake, LT1 cam and stayed with 1.5 rockers, you'd be way better than the TPI
i personally am doing the LT1 intake, LT4 Hot Cam, with 1.5 RR
BUT.. the limiting factor will then change to heads.. the L98's will not flow what i need them to flow in order to take advantage of this set up.
so are you doing this on your 305??? a few people have done it.. not sure what heads they used, but you really need to open up your stock heads to see good gains.
hope this helps.. some one else might want to chime in here..
Supreme Member
The best known cure for 305 heads and porting them is Sitting Bull's thread here.
For the cam, you can go anything you want as long as you don't go beyond about .500 lift as that's where the ported 416's stall out at on a 3.75" bore and the 1.94 intake valves. Something closer to stock will minimize your tuning efforts though, so choose according to your abilities.
1.) Your spring should match your cam. Look for max lift, seat psi at installed height, and compressed psi/height.
2.) Again, depends on the cam chosen. Dyno it, then you'll know where to change the shift points to... With the auto trans, that's a bit of extra work though since most trans shift kits have the reworked shift points already picked out...
3.) Forget about number 3 unless you're dead set on not learning to reprogram your ECU. If that's the case, go with the LT1 cam as it does run quite well on the stock tune.
For the cam, you can go anything you want as long as you don't go beyond about .500 lift as that's where the ported 416's stall out at on a 3.75" bore and the 1.94 intake valves. Something closer to stock will minimize your tuning efforts though, so choose according to your abilities.
1.) Your spring should match your cam. Look for max lift, seat psi at installed height, and compressed psi/height.
2.) Again, depends on the cam chosen. Dyno it, then you'll know where to change the shift points to... With the auto trans, that's a bit of extra work though since most trans shift kits have the reworked shift points already picked out...
3.) Forget about number 3 unless you're dead set on not learning to reprogram your ECU. If that's the case, go with the LT1 cam as it does run quite well on the stock tune.