okay heres the deal and i honestly spent a half hour in the search tab trying to find this but info is scarce since nobody gives a **** over LS motors but, which flows better a PR4 or a P75 intake manifold?

my setup incase anyone is wondering
B18B
YS1 Transmission
B20 Cams
Wiseco 11.5 compression pistons
Eagle H beam rods,
Balanced and Micropolished crank
N1 crank pulley
Yokana Header (am getting PLM Header)



I have both manifolds in my garage and i can see visual differences, the PR4 looks like it has a large plenum so im wondering which one flows better?
pr4 left, p75 right


p75 left, pr4 right


Anyone ever flow tested these?

 

shorter runners and bigger plenuem is better for top end power, vice versa for down low. sorry, thats all i got

 

well the one with a big plenum has long runners

 

They both are very similar but the accurate truth is that the minor differences between manifolds aren't going to translate to any notable variance in power output.

At this point of your build, this the least of your worries.
IMHO I would just fork over some cash and get a used blox. I've seen them go for $80-140 used.

Get everything else and worry about the IM later pal.
If anything we can test both out on the dyno on a dyno-after-dark session this winter.

I do have a GSR IM that I could try to get it to fit on the LS head. I'd like to see how that does do.

Charlie Moua

 

hey charlie if you wanna bring that to rockfalls tomorrow ill buy it off you since i can hack up one of the LS intakes and i got a friend whos a career welder