Originally Posted by
vertigo
Lets break this down:
a) True or false: Full-Race is a company, they sell what people will buy, no one wants to spend $1200+ on a bottom mount manifold. And people that buy full-race manifolds are more likely to run very large turbos.
b) True or false: Top mounts are more likely to melt the BMC?
c) True or false: Top mounts are more likely to melt oil lines?
d) True or false: Top mounts generally don't run water lines (yes I know many large turbos are not water cooled).
e) True or false: If the turbo manages to avoid the a/c compressor and mount, the intercooler piping will have less bends being run along the bottom.
f) True or false: If the turbo manages to avoid the a/c compressor and mount, the downpipe will be shorter, and have less of a bend.
A - First part true, second part not true, third part true
B - False
C - False (should be phrased "top mounts are more likely to cause oiling problems")
D - True, but this depends on the turbo and not the placement
E - Depends on how the housing is clocked
F - Not sure what you're trying to ask...
How about servicability on that bottom mount manifold, eh? Having fun replacing those banjo bolts behind the compressor housing?
Regarding the manifold at hand:
I'm sure you can work the runner design and collector out. A straight shot with a more gradual collector will help spool, but it may be pretty negligable.
As far as the welding goes - backpurging is always preferred when possible, but using the proper current setting and proper amount of filler may be your best bet for the winning combination of strength, pennetration, looks and flow. Your welds look superb, but with that degree of undercut you may run into issues with cracking at the weld. Schedule 40 is a wonderful sizing system to use since it just about welds itself and is easy to work with, but too much undercut and you effectively reduce the wall size.
What diameter are your primaries? Do you have a shot of the header flange from the port side? (sorry if I missed these things)