[tc33]

Searched through the site and found some old posts on the subject. Most were negative.

I have a crate 383 small block with Holley Commander 950 EFI installed.

My question is will a throttle body spacer on the EFI setup provide the same performance boost in the mid range that you get with a carb'd engine??

I had a 1 inch spacer installed on a 327 in my last street rod and there was a noticeable difference (positive difference compared with no spacer). The 327 had an Edlebrock 650 4BBL. Looking for opinions...

[crussell85]

do you have a big enough fuel pump to supply that throttle body? there shouldn't be a difference between carb and throttle body, if anything you should get more out of the throttle body if you are set up correctly for it.

[curtis73]

Most back to back tests on spacers (carb or throttle body EFI) show mixed results. The old thought was open spacers increased plenum volume which favors HP and 4-hole spacers increase velocity which helps torque. In truth, it depends on many factors. I put a 4-hole spacer on my pontiac 389 and gained HP and lost torque... of course it was dynoed on two different days and corrected for STP, so who knows if the numbers were apples to apples.

I think the best way to test is just to use timeslips or a Gtech meter. Do 5 runs without it, then 5 runs with it and see what happens.