[Nemeth]

Hello every one I had a 4 hole spacer atop my performer rpm air gap it really did not pull well.I have a sbc 383 rhs heads 180 cc runners 10.5 to 1 comp 236-242 @ ,050 .550 lift 110 lsa.670 worked avenger.
I installed a 1 inch open spacer....engine came to life and pulls hard mid range.
Seems an engine with after market heads and a decent size cam with a dual plane manifold do much better with open spacers.

How ever an engine with mild build like my 327 with vortec heads performer intake,600 eddy carb comp 218-224 @ .050 9 to1 comp run better with a 1 inch 4 hole spacer.Smaller builds need more velocity for the low end torque.

That is my conclusion after testing both engines with different spacers....

SO YES SPACERS USUALLY DO MAKE A BIG IMPACT ON ENGINE PERFORMANCE !!!!!!!!!!!!!

[techinspector1]

Good on ya mate, for experimenting.

For you other gearheads out there......
Each motor combination is different, so there is no set of rules as to the configuration or height of spacer(s) to use. Try different spacers and combinations of spacers to find if they help your combination.

[Richiehd]

I installed a 1 inch Super Sucker on my 350. World heads, 200 cc runners solid lifter cam. It really woke up the mid range from 3000 to 5500

[Nemeth]

Well I got so many different answers that I went and bit the bullet and bought several sizes of 4 hole and opens.... Funny the guy at the speed shop told me an open spacer would kill my torque all around....wrong made the bottom a little softer but between 2600 to 6000 I gained a whole lot more seat of the pants pull made me much happier with my build!!!! Was starting to think 383 was a bad choice but know my mind is changing...

Well lets see wat an open hole 1.5 spacer dose.Also I think my dissy advance springs are to tight cause It advances kinda slow when throttle is snapped. Ill try a curve kit and hope nothins wrong with my HEI.

Got to read and experiment first.....before questions are asked and to many wrong answers are given!!!!