Speedmaster heads on a 403

Reply Subscribe

Thread Tools

Search this Thread

November 11th, 2023, 08:03 AM

Jschevys

Registered User

Thread Starter

Join Date: Nov 2023

Posts: 27

Speedmaster heads on a 403

Can anyone share any information on using the Speedmaster heads on a small block 403?
I'm planning on doing it, so any info would be a great help.

November 11th, 2023, 09:48 AM

olds 307 and 403

Out of Line, Everytime😉

Join Date: Dec 2006

Location: Melville, Saskatchewan

Posts: 8,952

The head bolt holes need enlarged to fit 1/2" head bolts. They are 80+ cc out of box, what pistons are you using? Also a mechanical fuel pump won't work. Good luck.

November 11th, 2023, 10:56 AM

Jschevys

Registered User

Thread Starter

Join Date: Nov 2023

Posts: 27

Was planning on putting flat tops In it. Mondello is the only place that has them that I can find. Don't know about Racetch in CA. They don't list them on their site.

November 11th, 2023, 11:19 AM

olds 307 and 403

Out of Line, Everytime😉

Join Date: Dec 2006

Location: Melville, Saskatchewan

Posts: 8,952

Talk to Cutlassefi. He helped bring those Racetec pistons to the market and has done multiple builds with the Speedmaster heads. He even offers a CNC ported version.

November 12th, 2023, 03:15 PM

70W-32

Registered User

Join Date: Mar 2013

Location: St. Clair, MI

Posts: 1,649

Quote:

Originally Posted by Jschevys

Was planning on putting flat tops In it. Mondello is the only place that has them that I can find. Don't know about Racetch in CA. They don't list them on their site.

You'd be wise to do a review search on Mondello Performance before spending your money there, they have a pretty poor reputation, the owner died recently, and no one seems to know whos running the joint now.