Hello,

Will big bore head gaskets be necessary for a 3.875 bore?

Also;

What are the ideal deck clearances for shim head gaskets and composition gaskets? I'll be using either posted G or 471 heads. The Gs will go on a 292 B9AE block bored .040 with a 312 crank with flattops. The 471s will go on a ECZ 312 bored to 3.875 with 17cc domed pistons for which I'll need the composition gaskets. (Do I figure .041 thick?) I'm shooting for about 10-10.25/1 compression. I plan on using an Isky RPM 300 (228 deg.@.050) in either combination. I need to decide which way to go for a hot street engine for my 57 Ranchero with T-85 O.D. and 4.30 cogs. Any help will be greatly appreciated!

And will a modern paxton blower bolt to the OE F code bracket? Just curious.

THANKS!

FIGHT CONFORMITY! 

I personally like 0.040” clearance between the piston and the head.  This gives about a 0.005”-0.008” safety margin when everything is heated up and at rpm.  With composition head gaskets, the piston being level with the deck or just slightly out will get you there.  With steel shim head gaskets, this would requre the piston to be about 0.015” in the hole.

Lorena, Texas (South of Waco)

Ted;

I don't know if you use John M's Best head gaskets, but was wondering if you need to re-torque after the motor has been run for a few hundred miles. With the Fel-Pro Perma Torque gaskets, I didn't re-torque and never had any problems. I hate having to remove the rocker arm assemblies and loose my dialed in adjustments. I'm just sayin'

Rono

  Ron Lane,  Meridian, ID

Without actually putting the Best Gaskets or FelPro head gaskets on a 3.875” bore block, I’ll step out on a limb and say that the standard gaskets will work without having to move up to the big bore gaskets made by Best Gasket.  I use the standard gaskets regularly on 3.860" bores.

Although the original equipment steel shim head gaskets call for being retorqued after the engine has been run, I do not retorque any composition gaskets.  If the composition gaskets do not cinch down adequately during the initial torquing of the heads, then there are other problems present that retorquing is likely only delaying.  Gasket technology has come too far since the early Fifties for retorquing to even be considered with modern gasket designs.  For anyone using the original oem steel gaskets then by all means go by recommendations in the service manuals for those gaskets.

I do prefer the Best Gasket brand over the FelPros when given a choice but do not have any performance issues with either.  Spongy head bolts are the biggest problem I come across.  I do insure that all head bolts are grade eight and not the originals though.  The factory installed head bolts were not the best when they are new and a half of century of fatigue has helped either.

Lorena, Texas (South of Waco)

Thanks for the info. This forum is the greatest!

I tore down the B9AE engine over the weekend. It was pulled from a garbage truck years ago and and was said to be a good runner. I knew it had a forged crank and was hoping it had C1TE rods and had not been over bored much (I was aware that it had been re-built at some point).

Unfortunately the bore is 3.840 and the rods are EBU. I wanted to use this block with a 312 crank and C1TE rods, which are 6.254" long from what I can gather, IS THIS LENGTH CORRECT?

I have a set of +.040 312 TRW forged pistons...3.840 and although there is no ridge in the bores and honing marks are still visible I don't know if I can get away with just honing it and using my pistons. What kind of piston clearance would I need? .007?




FIGHT CONFORMITY! 

The L2018F TRW pistons don't need that much clearance. .0025-.0035" should be fine. If the bores are good I would use the block. The early HD 292's thru 1960 used the cast 292 crankshaft and 312 rods with tall piston.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico