Right now I'm down to the cam selection, but didnt know if it will work with sd. Right now have a 400 sbc with lt headers, MR or HSR, and AFR 220. I'm putting it in a 90' formula with a t56. The cam I'm going with will be the XER 242/248 112 LSA, but I don't know if it will have enough vacum for the sd to work. I dont want to get this all done and find out that the thing wont run bcuz the cam is too big.

Thanks for the help
Jeremy

 

If you are worried about it you can always get a vacuum booster.

 

Will that solve the poor vacum signal for the MAP sensor that happens with bigger cams?

 

take into account that a 400 usually "swallows" a cam...
do a comparison on duration.
a 305 with a HOT LT4 cam, and World heads runs fine with a gm ecm and speed density.
the HOT LT4 cam is 219 / 229 on 112lsa

If it were me, I'd get a copy of Desktop Dyno, and do a cam comparison based on your setup.
I found out when I was playing with similar cams on mine, that a cam with shorter duration and a bit more lift made more power.
I'm going that route, to make sure there are no programming issues.
I found one with 230 /238 on 112 lsa that should scream.
given the difference in displacement, it should do fine for drivability.

good luck!!

my .02

chris400