Title says it all. My 2056 was built using 1.8L heads (4 bolt pattern) so I can either use the 1.7L or 1.8L manifolds. Which will provide better flow? Any data to back it up?

What plenum do you have??

The 1.7 runners are the smallest diameter, they build torque but hurt RPM..

I believe the 1.8 runners are the same diameter as the 2.0 runners. That would allow you to use a 2.0 intake as well.

Are you using D-Jet or L-Jet?

All built off a once stock 1.7L D-jet. So, I'm using a 1.7L plenum but I'm willing to switch to the 2.0L if a benefit is to be had by doing so. I'm getting a 2.0L throttle body, and 2.0L injectors to go along w/the setup. My MPS was adjusted by Geoff (Bleyseng) based on his 2056 setup. I'll fine tune it w/a a/f meter and dyno once the parts are all in order.

-pt

Nope, 2.0 runners are larger diameter and shorter than all the rest..

Conclusions:

1.7L manifolds have a smaller diameter, will produce more torque, less power response @ higher RPM's

1.8L manifolds have a larger diameter, wil produce less torque, more power responsee @ higher RPM's

Cool. I'm going to try out the 1.8L manifolds b/c the webcam 73 performs best from about 3 to 4.5k rpm's. My fun driving is done at these levels on windy roads.

I'll keep the 1.7L plenum b/c it sounds like the 2.0L plenum will not line up w/the other manifolds.

Thanks for all the help.

-pt

Curious as to what kind HP/Tq. numbers that motor will make.
Compression ratio? vs. Cam profile?
Bet ya don't make much more than a well tuned 2.0L

See Jake I've been listening.

CR is ~ 8.6:1. Webcam 73 grind w/matching lifters. Was hoping for 115ish hp.

-pt