Re: mixing early/late BBC parts
 

Ken, the truck had 3.73 gears. You don't need 4.10 gears if you build enough torque.

I had a converted Allison AT545 converter, a big cooler, and a Derale extra deep cooler pan. I built my own 400TH. The stock one would not hold the torque.

Have you considered a bolt on overdrive unit? I think Strange still makes one.

I had a Weiand dual plane, a 2" spacer, and an 800CFM Q-Jet on it. If I weren't going with fuel injection, I'd probably use a Performer RPM Air Gap.

The Vortec heads are probably your best bet, if you use the old heads like I did, you'll need to put a full set of hardened seats in them. I think we're getting close to $300 to put 16 seats in. Another thought is a new set of the 100cc Edelbrock heads.

In order to run high compression (up to 10.5:1 is good) you need to have it at zero deck, quench and squish is critical to killing detonation, it won't work if you don't do it. You'll need forged pistons, if you were to get in a bind with a tank of bad gas you could easily kill any cast piston.

The trick here is you won't be running much timing, maybe 12 initial at 800 RPM, and 34 total at around 3200, with a limiter on the vacuum advance,(I had an MSD system on mine) keeping the vacuum advance from pulling in more than 10-12 degrees. If you have plenty of compression, you do not need, and cannot use, timing to make cylinder pressure. You'll have to tune the timing.

I also had an oil cooler, and a fully tricked out cooling system so that my coolant temp stayed around 160-180 degrees. With no hot oil flowing through the radiator from the engine or transmission, a good water pump, a 7 blade clutch fan, and a good radiator, I had no problems.

I don't think I'd stroke it with that gear (if you had an overdrive on it I might), unless the trailer is massive. More displacement will hurt mileage, and you should have incredible power.

I had Hedman 1 3/4" headers on it, 3" collectors, and 3" pipes, with massive Flowmaster mufflers.

The engine made 450HP and 450 foot pounds of torque, peak HP was around 5300-5500, peak torque was around 3700. It ran for about 200K miles, most of it towing various trailers, before Dad wrecked the truck. The engine had very little wear in it, the block is going in the race car in a week or so.

Were I doing this again, I'd likely build a 496, use two TBI units on an Edelbrock intake (either that or I'd actually prefer a 1000cfm throttle body for a tuned port on an oval port tunnel ram and port injection) and Edelbrock heads, and back it with a 4L80E.