Originally Posted by F-BIRD'88

Yup you got the story.. We are all waiting on cams pistons bearings and more.. The supply chain all over is a big mess..
That TFS track max cam: If you want to run high ratio rockers on it be sure your valve springs are up to that job.. The rocker ratio has a multiplying effect on the VALVE MOTION. it multiplies lift AND it multiplies Valve motion open close acceleration/ deceleration... ( The valve moves quicker faster farther open close) This needs better valve spring control.. Thats why the LT-4 engine and the high perf LS engines use light weight valves..
as the OEMs like to run as little valve spring seat/ open force as they can get away with.
Standard weight valves with high rocker ratio will need more spring force fir X rpm limit.
That TFS .530" lift cam I would stay with a 1.5 rocker ratio on that one for the street. It still needs good springs . There is no free lunch in all thus stuff. Increased valve motion needs better spring control.

Originally Posted by F-BIRD'88

Yes.. The exhaust lift is not that critical on a sbc.
on the exhaust side it is all about the duration and thus actual exhaust open close events.
Thus a 1.6 in/ 1.5 ex ratio set is very popular.
.net .528"/.503" at the valve.
Its the intake side on a SBC that benefits by using increased intake rocker ratio for more intake valve lift..
Especially if when the cams intake duration is mild as these ALL are.

The LT-4 cam will run fine with 1.5 rockers.
and should benefit from either a 1.6/1.5 set or 1.6/1.6.
Onany cam like these ALL if you want to tame the overall net effect of cam OVERLAP a bit,
then choose the lower 1.5:1 exhaust side rocker ratio.
(1.6/1.5)
This tames the idle just a hair.
You can also advance the cam a bit too to tame the idle vaccum a hair.
EG the hot cam is 109/115 centers (112 LSA) thus its 3 degrees advanced.
To close the exhaust valve a hair earlier advance that cam a but more to say 107/117 centers. its now 5 degrees advanced.. The combibed effect will tame the idle vaccum a small amount if that is critical.
Same same with the Melling cam. eg 104/116 centers. Exhaust valve closes a hair earlier..
If the GM LT-4 cam DOES run in these TPI engines with the GM computer I'd say all these others will also. They are all very comparable.

If it is known that the GM LT-4 hot cam causes the TPI computer to foul up the drivability then all these other very similsr cams will also likely cause same issues.
I cannot see it needing more than a change in the base timing and basic timing curve a bit.
( You want the same same max WOT spark timing.
SBC 34-36 deg BTDC @ WOT rpm.)
All these cams will like increased base idle timing to idle best and creat the best idle manifold vacuum. All of them.

Originally Posted by EDGE

I ordered a Lingenfelter 74211 along with 1.6 Rockers. Thanks for all the input. I've learned the following hierarchy:

1: Selecting a Camshaft
2: Nuclear reactors

Originally Posted by Thirdgen89GTA

I had that cam in my L98 bolton. I was happy enough with it, but it will not play happy with a stock tune.

Originally Posted by Thirdgen89GTA

Something like what I'm running with 66° overlap even makes my LT1 painful at low RPM, the computer does not deal with it well.

Originally Posted by Orr89RocZ

Long tube runner tpi will still run way out of breath by 5000 or so. Cam might help it hang on some but not enough duration on the lpe 211 to get there. 5500-5600 needs shorter runners. Siamesed could help.

ran the hot cam clone from lunati on a L98, with big mouth tpi parts. Ran well. Required abit if tuning but wasnt hard at all. Ran good idled well and made ok power. It really needs short runners to work well like the lt1 intakes. It will make like 270’s whp on a tpi intake afr 180 head l98 at like 4400-4500 and on a tfs 195 lt1 6 spd car it makes 355 at 6200-6400. Lol so much power on the table

hell even the stock headed automatic lt1 with comp 220/230 cc305 cam made 300 whp at 5800-5900.

Thats why i dont think tpi cams really matter, the intake really controls what happens. Its gonna have a strong wave tune in that 4400 range. So cam doesn’t need to be big but sometimes over camming can help hold some power out beyond 4500-5000.

Originally Posted by skinny z

Interesting.
In a carbed application I've managed 71° of overlap reasonably well. While the idle vacuum wasn't great at 10" @ 850 RPM, most of that I put down to very worn shortblock. Cranking compression was down better than 25% across the board. The static compression ratio wasn't ideal either.
I suppose tuning is relative. With some tuning software/hardware the adjustments are easy and infinite. Others, maybe not so much. With a carb and mechanical distributor, the adjustments are infinite but incredibly cumbersome.

Originally Posted by Thirdgen89GTA

When I say low RPM, I mean basically anything off-idle to about 1700rpm. The engine HATES, and barely makes enough power to get out of its own way. While I can run the car in 6th gear at say 60mph, there is zero acceleration on-top unless I downshift. I usually keep the car in 5th gear until I'm consistently above 70mph. My car is running an M29 T56, with 3.23's, so the lower gears like 1, 2, and 3 are very widely spaced, makes the car feel slower than it is on the street because it falls out of its power band anytime you don't ring it out to 7000 on the upshift.