jplee6770

which block is better to build stroker

Run to Rund

455 has clearance cast in for connecting rod nuts with the longer stroke.

jplee6770

I think I asked the wrong question. Considering 425 block 389244D would it be better to build a 500 or would 1 of the 455's be better. Im looking at strength and block material composition. Thanks

joe_padavano

The block strength is the same. As noted, the 425 has a 3.980" stroke, the 455 has a 4.250" stroke, so the 455 is already a "stroker". The 455 blocks all have 0.842" diameter lifter bores at 39 degree lifter bank angle. Depending on the year and casting, the 425 could have 0.842" lifters at 45 deg, 0.921" lifters at 45 deg, or 0.921" lifters at 39 deg. The small lifter, 39 deg configuration is easiest to get cams and lifters for. If you are planning on having the original crank stroked, the 425 crank is forged, the 455 is almost certainly cast. If you are using an aftermarket crank, this is irrelevant.

lshlsh2

Would this be a time maybe to look at the new Rocket Racing block? Just a thought.

jplee6770

67 442 20 years as a c/sa nhra drag car, replicating a b/mp nhra 1968 nostalgia racer. hense, ideally I would like to see the 425 at 500ci under the hood (for the block #s) this class would actually run the 425 with dual quads, just upping the power level a bit. but the cross ram would look great under there

Kennybill

Interesting. Was C/SA for the factory 400 ci E block? Also was B/MP because the 400 E block was switched for the 425 D block and/or 2 four barrels? Is this build going to be automatic or stick shift. Thanks.

jplee6770

the 442 is an auto which is the a in c/sa, new England had many 425 conversions they were cheap in the 60s. in modified production class almost any motor mod was legal.google brainbeau olds to see how these 400e cars ran in c/s in 66, 67 & 68

Run to Rund

The 425 could be 45 deg with .842 lifters, 389244D, 1966; or 39 deg. with .842" in 1967, or 39 deg. with .921" 389244D, Toro 66-7.

anthonyP

Seems the 425 had one of the best stroke to bore dimensions and made great race engines as is because of the idle ratio.

stan 65 cutlass

all great info guys, interested because i have a 65 425 on the engine stand, completely rebuilt 9 1/2 to 1, never ran since rebuild, just not sure if i should replace the 74 olds 350 that runs like a bear already. i still need to pull the crank out of the 425 and get it drilled for my trans though. i was thinking with a Torker and a better cam the 425 should easily better the 350

stan 65 cutlass

ive been concerned my 425 may be a slug as a stocker but it sounds like you guys seem think otherwise, time to get busy!!

therobski

Stan, Instead of drilling out the back of the crank, I used a "thin" throw out bearing and made sure the input shaft on the Muncie did not touch the back of the crank on my beastly 500HP 455 in the 67 I sold last year.(some will touch some will not-needs a tiny pocket of air space) I Believe I bought the bearing from Bill Travato, not 100% sure. Although it was not a daily driver by no means, I did not have an issue in over 8 years. Just a thought For the 64 F-85, I have a 65 386525A 425 block on my engine stand with a stash of goodies I have collected including new Arias custom made 30 over pistons, set of rods that Joe Mondello himself worked over! I may have Cutlass EFI (Mark) build the 425 for me. Right now a 67 400E is in the car with some freeze plug issues I need to take care of. The car was built based on 450 plus HP 425 build from the start. I would only need to change the torque converter to accommodate the 425. It's taken me 7 years to get the car this far and getting closer to the retiring option. So if I'm going to build the 425 I need to do it while I'm gainfully employed

stan 65 cutlass

great info rob, i will look into that bearing for sure, what intake is on the 64, it looks taller than stock and your hood closes