I was curious at to the difference between the Crawford Plenum and the Motordyne Spacer 3/8? Is there a performace difference between the two? Is the a design difference between the two? Is it just a matter of preference of brand name? Thanks in advance

 

It seems that it is just a matter of preference. As regards performance, it seems that the gains are similar in both.
I have read that the quality as well as the fit and finish of the both are normally very good. There have been some issues with some of the aftermarket plennums cracking however but I beleive that those issues have been worked out. The major difference between the two is that with the spacer, you now have two gaskets/attachment points and with the plenum there is only one. Maintenance, should it be required on either, should be quick and easy.

From my standpoint I feel that you get more bang for your buck out of the spacer and you get to keep your stock look.

 

Do a search, there are several threads with differing points of view. I have a Motordyne 3/8" Spacer, and pleased with the performance & investment.