Split from the TMI 400 project thread:

Lets see if I get this right. 4 in bore & 4.25 in stroke = 427 cu in? Is this practical? I thought the 4 in stroke was all you could get out of the block.

 

How about 4.060 bore x 4.25" bore for 440 cu inches. There have been 400s which were bored and stroked to 432 cu inches (4.17" stroke). To my knowledge no one has done a 4.25" stroke, but it is possible.

 

During the build up of my 400, we used an Eagle forged crank which had smaller counter weights than the factory crank. Once we had it in, the most restrictive point in the crankcase had more than 0.25" clearance between it and the counterweight. My machinist believed we could fit a 4.33" stroke crank with a little massaging. But again, this was an aftermarket crank. I don't think you could get away with too much on an offset ground factory crank.

--J

 

Eagle and SCAT make a 4.25" forged crank for a Windsor. You could use a 6.25" chevy rod and a TRW forged piston for a 351M. You might have to take a little off the piston and bush the rod. A longer rod and shorter piston would be preferable, but this should be cheap and reliable.

 

Sorry, the piston pin is larger than the large end of the rod, but it can be done.

 

This could be fun. Brought out the calculator and it says 4.06 Bore and 4.14 stroke give 429 cu in. Pop on some boss heads and you'd have a lighter Boss 429? That would be interesting in a Mustang (not exactly F.T.E. item but the mind never stops working, well almost never.)

 

Boss 429 heads won't even come close to fitting. Different bore spacing: 385 Series is 4.9", 335 Series is 4.38".

--J

 

If you gotta have a bigger Clevo, I'd go with a Eagle 4.25" crank and a 4.04" bore for a 436. If I wanted to spend another $15K for a 400, I'd go with a custom 4.33" crank and a 4.06" (or larger) bore, in a sleeved block, for a 448ci+ engine.

Since we are sorta talking "what ifs", I'd like to see someone come out with a 400 type block with W/C bellhousing and motor mounts, taller lifter bores like the roller cam Windsors, Windsor oiling, 0.20" max overbore capacity, and a 4.4" stroke capacity. You could build one heck of a motor with that......about 488ci (8ltr)! Could you see the look on the Chevy guys face when they are bragging about their 7ltr SBC and you pull out a 8ltr Clevo! That would be priceless. Sad thing is, I'm ready and able to drop cash on a block like this but I doubt any of us will see this come to market.

--J

 

http://www.strokerkits.com/351___400m.htm
Happy stroking.

Curtis

 

Wasn't talking about Boss 429 heads, was talking about Boss 351 heads (1971-72).

 

Umm. I'm running a set of virgin Boss 351 heads. It was pretty cool tearing the old FoMoCo box off of them. These have now been ported a little to clean the bowl up and improve low lift flow. I've already got them sold and the motor is still sitting in the dyno room. A set of CHI's will take their place.

--J