Originally Posted by stevemilz
I am putting together a new combo, so I need help deciding how thick of a carb spacer the motor needs. If I remember correctly carb'd 350's liked 2" spacers.
Brief over view:
Mahle 3.905 -4cc
Accufab 4150 style throttle body
Victor Jr. EFI port matched to "Cleaned up" stock heads
If you are trying for more power than the LSx or FAST folded hands manifold, you might look carefully at intake tuning on the Vic. The long runners are about 7.25 long and the short ones about 4.5 in. long. I don't think a cam designed for the OEM/FAST manifold will be ideal. IMO, the short/long runners ask for different valve timing for the inner cylinders from what the outer cylinders like. That's doable for a reasonable price.
High end engines like Nextel Cup treat each cylinder as a separate "engine" as far as valve timing goes. Treating an LS1 with the Vic manifold as 2 V4s on a common crank might prove worthwhile.
Plenum size on the Vic is about 35-40 cubic inches, which might be smaller than you need. An open 4150 spacer is about 12 cu. in. per inch of height.