4/71 blowers

Can anyone provide lower gasket o/d measurements for the GM 4/71 supercharger .Im building an inlet manifold for a 215 Buick and need a size for the intermediate plate ,the bolt hole centre spacing front to back and side to side. Gratcia .

 

Order a gasket from any blower manufacturer, BDS, Hampton, etc.

 

If you have a semi truck service dealer,namely Detroit Diesel,they might even have one in stock right there.Might be cheaper than a blower place too.

Jimmy D

 

I think www.blowerdriveservice.com has some dimensional information on all sizes of blowers - check it out

 

All measurements were taken right from my 1949 4-71. I hope this helps.

Feel free to follow up if you need any more info.

The overall width of a 4-71, at the base plate, is 12-5/8". The length is 10". The outside corners of the gasket have a 1" radius.

The 4 mounting holes are are 7/16". They are 11-5/16" wide, apart, and 6-7/8", front-to-back. There is no offset.

The bottom center hole is 3-7/8" wide, and 7-1/2" long. The corners of the center hole have a 1/2" radius. The hole is centered, front-to-back and side-to-side. So there is 1-1/4" ahead of, and behind the hole, and 4-1/4 on either side of it.

The top plate is 5-5/16" wide, and 9-13/16" long. The bolt holes are 4-7/16 wide, apart, and 8-5/8", front-to-back. The top bolts are 3/8" UNC.

The top hole is 3-7/8" wide, and 7-1/2" long, so a 3/4" border on each side, and 1-1/16" border on the front and back. The inside and outside corners have a 1/2" radius.