An inexpensive crank swap later, you can put 302 pistons in a 351w. Poor man's stroker! 393w These cranks use the compression height difference between the 302 and 351 pistons to get 393 cubes from a .030" over 351w using stock rods and off the shelf 302 pistons. In the end, you are only spending about 100 bux more than a straight 351w or 302 rebuild. Dave
I have used a 302 cam and firing order to make a winzer rev like there is no tomarrow I cant help with the pistons I heard that they will not fit
A 302 and 351 have the same size bore. Both share a 4 inch bore. Yes it will fit! But.... it wont work unless you do the poor mans stroker. Using a 302 piston in a 351 would mean the pistons would sit lower in the bore. As the stroke increases you need a longer rod. Why? Because on the down stroke if the rod isnt longer the piston comes to far out of the bottom of the bore. Why not just make the piston taller? Many reasons, friction from amount of surface area, more weight over the pin, heavier pistons, balancing issues. And Rod ratio which we wont get into. As the rod gets longer the piston CH(compression height) which is the top of the piston to the center of where the pin go's in becomes less. It very simple to find out what CH you need. Lets take a 408windsor. 4"stroke with a 6" rod, with a block dech height of 9.5.. heres the math (half stroke+Rodlength)-deck height = Compression height. So here is the math assumin all 9.5 blocks 6" rods 408 needs a 1.5CH piston (6rod+(1/2 stroke))-deck height=1.5 6.125 408 needs a 1.375CH piston 6.2rod ina 408 needs 1.30 CH piston SO now for yours a 351 has 3.5" stroke so take half that 1.75" now your stock rods I think are 5.956. (1.75+5.956)-9.5=1.79CH = 1.794 a 302 piston has 1 .60 I think not 100% sure so now a 302 in a 351 would sit .190" lower in the bore. So how does it work then, well a poor mans stroker uses an offset stroke, in other words I think it was something like 3.83" stroke..not really sure so lets reverse the math and know for sure. Now we know the 1.6piston+ rod 5.956 = 7.556... minus deck height 9.5" leaves us with 1.94" thats half stroke, so double it, now you need a crank with 3.88" of stroke to use a 302 piston. So I was wrong its not a 3.83" stroke its a 3.88", thank god for math
Alrighty then !!! I've always admired people that figure that stuff out. I for one prefer to be told what to use and just bolt it in !!! Thanks for the info.
He said the same thing I said in my post, just with much greater detail. The crank he is talking about is a 3.85" stroke. Just look at Summit's site for a 393w stroker crank. It uses run of the mill 302 pistons and your stock 351w rods. So it is a very cost effective mod. Not much more than a stock rebuild if you get a cast crank. I have seen them as low as 299. After you turn you stock cast crank, you could have had a new stroker for only a little more. Then the 302 pistons are less than stock 351w replacement pistons. That is what he was getting at with 'poor man's stroker'. It's cheap to do. Dave
