390 Rebuild

dgrant09 · #1 (**permalink**) 05-05-2008, 01:32 AM

Well our leaking head gasket (I hope that is what caused the water in the oil) lead to a compression check and that was in the dumps across the board. We will be rebuilding it with a stock kit. I saw a kit in a catalog in which the cam in the kit could be replaced for a RV cam for an additional $20.00. What would this do for overall mileage and performance?
Thanks

Redmanbob · #2 (**permalink**) 05-05-2008, 09:34 AM

If it's the kit from fastengineparts the cam is just a step up from stock. It seems to make a nice difference in lower end on the 352 and has pretty good pull no matter what. So it would seem to make sense it will be fine in a 390.

dgrant09 · #3 (**permalink**) 05-06-2008, 11:15 PM

Quote:

Originally Posted by Redmanbob

If it's the kit from fastengineparts the cam is just a step up from stock. It seems to make a nice difference in lower end on the 352 and has pretty good pull no matter what. So it would seem to make sense it will be fine in a 390.

I'll be able to finish the tear down this coming weekend and get into ordering parts. Will this reduce mileage? We'll check with our parts person and see if we'll be able to step up the cam with the engine kit.

390428cjt · #4 (**permalink**) 05-12-2008, 10:34 AM

comp cam 270H is a little better upgrade dont expect big milage gains with any FE motor just performance gains for the same gas useage

dgrant09 · #5 (**permalink**) 05-12-2008, 10:50 AM

Thanks for the info!!
We did finish the tear down and only the intake gasket appeared to be leaking (3 ports) with small scaring on two crankshaft journals. Hope the block is not cracked, taking it all in for a hot wash and magna flux today.
One surprise was to find the block has been bored before, .30 over then so we'll go to .60.
A couple of the young shop folks (they help us dummies) were surprised at the wear on the piston and low compression # and the truck was still running (low was around 5 and a high of 30). I suppose that shows how tough these old engines are!
As mentioned above we will be going with the cam to help with the low end. With the compression # above, the rebuild alone will be a significant improvement in performance..