The 352 was once the epitome of FE performance , in 1958 it introduced the world to the mighty FE. for the next three years the 352 rained supreme in the world of Ford. As the world progressed into a cubic inch race the 352 was regulated to a truck engine or as the base model in cars. Now as parts become more scarce the 352 is still available and is running in quite a few vehicles out there. The 352 was produced with a 4.00 bore and a 3.50 stroke but options for increased cubic inches are limited. Common practice is to bore it .050 and add a 390 crank, rods, and pistons, with the .050 over bore today's availability of stokers from Eagle and Scat you can bump upwards of 430 cid. But what if your block cant take the bore or you don't want to use your block up just to reach the 390 bore size? Then there is the other issue and that is cost , not everyone has $1800+ plus for a stroker kit . We were setting around last fall and were talking about how to make a 352 with more displacement . Looking at a piston chart we knew the 4.00 bore was no problem but finding a pin height that would work was the challenge. Soon we settled on a Sealed Power 302 ford piston that had a full floating wrist pin, problem #1 solved . Pin height was the next challenge, looking at the H273CP it had a 1.605 compression distance , a 428 uses a 1.672 so we are .067 short. But a 352 ford rod is 6.542 which is .052 longer than a 390 rod so we are getting into the ballpark now, a .017-.020 piston to deck clearance is workable. So lets recap, 352 block and rods, 302 pistons, and a 428 crank. We already had the block and rods, a Sealed Power hypereutic piston set with pins , moly rings , and retainers was bought at a cost of $195 then a 428 crank was found for $300 in need of turning (though a Eagle or Scat could be sourced for $400-$600) . The 352 is now a 4.00+ bore and a 3.98 stroke giving us a 400+cid combination , it is a "square " engine, meaning bore and stroke are equal . As anyone who has owned a 400 Modified Ford engine will attest this is a very torquey ratio. Using the factory 352 rod limits this engine to a low rpm but if you started with a 352 then you were already limited by the rods. The most in depth machine work necessary is to narrow the small end of the rod to a 302 rod width or .312. The next hurdle is the wrist pin difference the 352 uses a .975 and a 302 uses a .912. A bushing for an Eagle 302 rod was used and by honing the existing FE bushing out and pressing the 302 busing in it allows the 302 wrist pin to be used . Now I was concerned about running a bushing inside a bushing but after consulting with a few high end builders they assured me that it is more than safe at these power levels, by the time I build the next engine I will have custom bushing made in bulk by then. Engine System in Tucker Ga. did the machine work and as always it was top notch. I had this one internally balanced but a 428 flywheel would save some cost on internally balancing . Cost can come in for around $1000 or less if you are frugal in your shopping, that's about half what you would spend on a Eagle or Scat kit, maybe not as cheap as a conversion to a 390 but your block will be good for a few more overbores and rebuilds this way. It is just one option in the wide world for our beloved engines. Next installment will be when assemble the short block, part three will be in the truck and ran on a chassis dyno.
PART 2
 |
| mocked up |
 |
| narrowing to 302 width |
 |
| size comparison still plenty strong |
 |
| Eagle bushing |
 |
| bushed to size |
 |
| Sealed Power H273CP |
 |
| .017 deck clearance |
Comments
Post a Comment