Cmpeirce123

Winter is approaching soon and I will be doing some upgrades to my 64 F85 this winter. I will be pulling my 425 out and installing a new cam, new th400 transmission to replace the 2 speed, and a new rear end to replace my 2.78 open.

The motor is out of a 1965 Delta 88 425. The paperwork I got with it says it is 10.25:1 compression. It’s been bored .030 over. A heads with roller rockers. I know it’s not that compression right now.

I figured I’d have some head work done while I have it torn apart. I have the fel pro head gaskets on it now. I believe I looked them up and they are .043 thickness. I see the original steel were .017 Should I go with a smaller head gasket such as Cometic .027 or should I have my heads milled down to get some compression back?

Motor will have the following

New cam specs are:

Advertised duration 292/296
Duration @.50 230/234
110 lobe sep
Valve lift .496/.504

Edlebrock performer intake
Holley 750 mechanical secondaries
Hei distributor
MSD ignition
long tube headers to 3” hooker aerochambers mufflers

Would having the heads milled or using a less thick head gasket make a real difference? Should I have any work done to the A heads or just save for Aluminum heads when the come out?

cutlassefi

Didn’t you get the Mahle piston for that?
if so I’d just mill the heads or buy aluminums with the appropriate size chamber.

Cmpeirce123

I’m not sure what the brand is. They were in the motor when I tore it down, cleaned it up, reringed them, and regasket and resealed it.