what needs done to 391 FT block to replace a 428 car block?

[jholmes217]

Besides a bushing for the distributor, is there anything else that needs done to this block to run it in the place of an FE?  My 428 CJ in my 1969 Mach 1 was already bored .060 when I bought the car.  There is a 391 FT short block for sale close to me for $150.  I don't know if it has "428" in the water jackets or "C" scratch on the back.  I plan to just use the block, not the rest of the FT rotating assembly.

[thatdarncat]

FT blocks usually have an oil return hole on the bottom side near the oil pan rail that was for the air compressor. It can just be plugged with a pipe plug.

[jholmes217]

FT blocks usually have an oil return hole on the bottom side near the oil pan rail that was for the air compressor. It can just be plugged with a pipe plug.

Thanks. 

[Lowrider]

Not a 428, but I used a FT block to repair a 406. I found the deck height with the FT left the pistons waaay more in the hole than I wanted. I think I had 0.015-0.020 taken off the deck and the pistons ended up where factory 406/427's in a FE block sat. Don't recall what the spec was.

[BH107]

Not a 428, but I used a FT block to repair a 406. I found the deck height with the FT left the pistons waaay more in the hole than I wanted. I think I had 0.015-0.020 taken off the deck and the pistons ended up where factory 406/427's in a FE block sat. Don't recall what the spec was.

Not sure about your combo, but 406 pistons were way down in the hole from the factory. All FE/FT blocks have the same deck height.

[BH107]

It's a gamble, and definitely have it sonic tested first. Not many will go to 4.13 bore without being thin.

[Lowrider]

Found the specs over on mercurystuff.com. 406 was .045-.065 IIRC that's what I measured before tear down. After taking .015/.020 off I got to the lower spec or just a few thousand more. This FT block must have had a hard life as it had a twist to it. End result is it runs fine, doesn't spark knock or overheat here in the Az. desert.