Boss 429 head

Tech Related Discussion

Boss 429 head

Postby beretta » Wed Dec 12, 2012 6:05 am

Looking for some suggestions on a repair for these heads. This is for my street car that I have had since I was in high school. Unlike most I kept it and glad I did cause this thing is worth some $$$$$....Anyway it got some leaking issues with oil and some coolant.
For those of you that don't know about this motor it does not use a conventional head gasket it uses an O-rings and sealing gasket
around the combustion chamber..
Here's the issue, some of the holes are not centered and after some time the O-ring collapses. Looking for some way to fix this
and I don't think welding is going to work as these heads and made out of aluminum scrap from what I am told..
Thanks Chad and others that want to help...
Posts: 52
Joined: Sun Dec 06, 2009 11:39 am
Location: USA

Re: Boss 429 head

Postby jmarkaudio » Wed Dec 12, 2012 8:43 am

Using a larger end mill move the hole back more centered, use a larger o-ring to fit.
Mark Whitener

Good work isn't cheap, and cheap work can't be good.
Posts: 605
Joined: Thu Nov 29, 2007 9:58 pm
Location: Florida

Re: Boss 429 head

Postby Adger Smith » Sat Dec 15, 2012 12:18 am

Those heads didn't use "O" rings. They used a cushion silicone biscuit with a steel reinforcement.
Back a few years ago I looked for the cushion silicone seals that went with the boss heads and No one had any. The customer(Billy Hines) looked for 3 years and it was holding up the restoration of his '70 boss Mustang. I decided to weld up all the fire rings in the heads as well as all the silicone seal holes and adapt a stock 429/460 head gasket. You redrill the correct cooling holes for water transfer through the block and head. This was in 1998 and the engine is still running strong with a reduced compression (9.8-1) in the Original Mustang. Runs cool in the parades it is driven in and cruises down the road on Rod Runs without any problems. Nice thing is, from the outside, it still looks stock even though it is a wet deck instead of the original dry deck design. WELDING works fine. I use the very same alloy rod I use when doing repair to Mercury Marine outboard blocks. If you find someone that knows the correct pre heat procedure you can have them welded and fixed without even warping or damaging the valve seats. If you can't do it or find someone to do it, box up the heads and send them to me. It will end all your troubles and you can enjoy your ride instead of working and having trouble with it.
Adger Smith
Adger Smith Performance Engines
2802 w 7 th st
Texarkana, Tx
903 794 7223 shop
903 824 4924 cell
Adger Smith
Posts: 147
Joined: Sat Nov 07, 2009 11:52 pm

Re: Boss 429 head

Postby SStrokerAce » Thu Feb 14, 2013 5:17 pm

Cometic can't make a head gasket for this?
Posts: 360
Joined: Wed Apr 15, 2009 9:13 am

Re: Boss 429 head

Postby Adger Smith » Fri Feb 15, 2013 2:20 am

you weld up all the silicone pad holes and the fire ring and redrill the head to fit a std 429/460 felpro gasket.
Adger Smith
Posts: 147
Joined: Sat Nov 07, 2009 11:52 pm

Re: Boss 429 head

Postby nomad » Sun Mar 03, 2013 7:35 am

I worked at Dearborn assembly as a roll test driver when those cars were made. As the stick shift driver I got lots of seat time in 429s and 302s.

One 429 didn't get sealed on one bank at the engine plant correctly. When I got it off the rollers it was smoking really bad. Drove it over the the engine repair bay for repairs and was told oil had finally worked it's way to the side of the blocks and coated the exhaust.

Most people thing Kar Kraft engineered the 429 install on the cars. They didn't. The Ford pilot plant did and KK just did the engine installs. No stickers, just the engine installs.

In the beginning they came down the line with 428s in them, we would drive them like any other car then they'd go to KK. When they came back we drove them again and sent them down the body line for the spoilers, all decals, and the price sticker. Later, they stopped doing the 428 thing and sent the engineless to KK. One black 429 was destroyed when the clamshell hoist putting cars on the final line failed and dropped the car on they floor.

The 69 Shelbys were handled in a similar fashion. They came down the line sans front end fiberglass and any other Shelby pieces. We drove those and shipped them out. They didn't come back though.
Posts: 138
Joined: Wed Nov 14, 2007 9:15 pm
Location: Auburndale, Florida

Return to General Talk

Who is online

Users browsing this forum: No registered users and 1 guest