[taff2]

We're building a budget big single combo for drag racing and I'd like to use a new old stock Crane Compucam solid roller cam and lifters I have on the shelf. It's big for a turbo combo so I'm planning to advance it a bit, 4 degrees or so sound about right?
The cam specs are - 260 Int/ 270 Ex @.050", lift .625" with 1.5 rocker ratio,
Int opens 25 BTDC and closes 55 ABDC,
Ex opens 66 BBDC and closes 24 ATDC,
LSA is 108 degrees.
So it has a EVC of 24 degrees and 49 degrees of overlap. Rpm range is spec'd at 4000 -7200 which is about spot on for what we want.
The combo is a 400 Pontiac, ported iron factory heads, compression ratio 10-1 on C16 with water/meth injection, single Bullseye billet compressor wheel of 83mm with the Race cover and a 96mm turbine wheel in a 1.58 turbine housing. Holley Super Sniper Stealth 4500 for fuelling.
We hope to make around 1250hp, a bit more later on with an injector upgrade.
Anyone using or has used a similar combo? Any advice appreciated.
ps, 2500lb car on radials,minimal exhaust system, a little bit of street cruising.

[JSPONT]

the LSA is the only thing that jumps out. For turbos I was told 112-114. But with that light car and all the other parts I think you will hit your goal.

[Tom Vaught]

I would go ahead and run it.
The tighter lobe separation with pass more fuel out of the exhaust, but on the old road race turbo cars we used to inject gas into the exhaust on the corners to keep the turbo spooled up. It does not hurt the turbo at all but you might need to do oil changes a bit more often as the excess fuel may go past the rings unless the engine is sealed up nicely.

Also as the power goes up the turbine housing usually needs to be larger but you have a smaller 400 cid engine. Go ahead and run it. JMO

Tom V.

[JSPONT]

My 1st cam with my turbo was a small hyd. w/ a 108 lsa, ran great until I blew a head gasket!!