Hey All, Obviously I'm new here and this might not be exactly the right place to post but I'm guessing that there are some knowledgeable people in here. Does anyone know the smallest stroke crankshaft that will fit in a 455 block? I searched quite a bit but it was hard to find journal sizes for all of the different blocks. It would preferably be a steel or even forged crank (from the factory or aftermarket). I know most people discourage less displacement, it's really just something I want to try. Thanks, Jeremy
Jeremy Years ago we destroked a buick crank by offset grinding to a small block chevy journal,2.00",from the buick 2.25" journal.resulted in a 3.65 stroke and really reved.Jim Bell also did this to compete in roundy round in the early 70's..the advantage ,besides high reving engine, is with the large 455 bore you can take advantage of the superior breathing of the stage 1 or 2 head. gary
That's exactly what I'm going for! I saw an ad for an aftermarket 455 block that can be ordered with a 4.495 bore and thought, 4.5" bore x 3.6" stroke = 458 that will really rev!!! To tell you the truth I'm really a chevy guy but when I saw the flow numbers on some of those stage 2/3 heads I was really impressed. Thanks for the info, Jeremy
Destroking 455 I thought about this too for reasons that will remain obscure. The only hint I will give is that a 3.48 stroke in a 455 gives just about 400 cubes, this would be an advantage in some situations. Keep in mind that the Buick has HUGE 3.25" main journals. This was done to reduce flexing of the crank and to allow less meat in the block. There are other issues to consider before you try to spin a big block Buick to 8500 RPM - like bearing speeds and the weak block.
John, I realize that the Buick big blocks aren't known to be bullet proof. I found this block www.paeenterprises.com/paeframe.html and figured it would do. But yeah, the higher the bore/stroke ratio or the more oversquare the better. I want this thing to run up to 8500 rpm where that motor can really use 350cfm+ from some good heads.
I'm 20, full time in college, full time as a loan officer, and mommy+daddy don't pay for anything!!! Of course, i spend 99% of my income on bills and my car, but who needs to eat every day, right?
Good choice on the Aftermarket Block! :TU: And good luck on this, keep us updated on what happens. :bglasses:
Keep in mind that the Buick has HUGE 3.25" main journals. Nailhead engines had forged cranks from the factory. they used the same bore spacing as the BBB's but they have much smaller journals. Nail cranks have been adapted for use in a BBB before though. a 455 with a crank from a: 401 / 425 would give 425.34 ci 364 would give 396.13 ci 264 / 322 would give 373.93 ci a 430 with a crank from a: 401 / 425 would give 401.04 ci 364 would give 373.50 ci 264 / 322 would give 352.57 ci given stock bores and strokes. of course, you'd have to have custom bearings or machined spaces of some kind put in the block in order to be able to do this. i don't think there'd be any point in trying to destroke the 400 as that engine already has too small of a bore to tolerate the Stage 1 valve sizes. if you're going to order one of the Bulldog blocks i believe one of the options on that is for a custom journal size. you could order it with Nail sized journals ... then alls ya gots to do is wait for it to show up. :laugh:
It's all about the combination. I don't feel with most head volumes(cc's) and heads flow on current cylinder heads that stroker combinations offer much benefit et-wise going down the track over what can be gain with the same money on port work to gain more air flow. If you look at the small-blocks that are out-running us, most have heads that flow as well or better than ours. The small blocks are making their power in a more useable rpm range going down the track. Plus when you consider our limited valvetrain abilities that just compounds the problem. I feel money is better spent in getting airflow vs cubic inches plus durability is increased by reducing the rotating assmbly weight. Exceptions would be cars 3900lbs+ but alot can be overcome by the proper converter setup. I say go for a destroked setup but don't go overboard as the rod length can get a little excessive in a hurry as you take the stroke out of the crank. I would say going to a 2.200 and destroking the crank .100" would be as far as I would go while still keeping things simple. It will be intersting to see what someone can do with the 425 Nailhead cranks and how well they hold up. It would be a much cheeper avenue of reliability over going with aftermarket cranks as well as a great way to reduce rotating weight. Especially if it caught on enough to have the volume to make it economical. As far as rpm, it's all about getting the oil to the bottom end. I feel the grooved main saddles is a good start but a larger groove in the main bearings offers a far greater benefit. I also feel there is alot of wasted energy with enlarging oil galleys in the feed section of the block on the pressure side. The block is weak enough, leave it alone. There is plenty of volume in the factory oil passages to feed the bearings especially when adding the oil line to the rear of the block. Work on getting the oil around the bearings and to the rods and also upgrading the oil pump with the aftermarket lower pump plate that Finish Line offers. That is the trick if you ask me. You may not get 8500 but if you got the heads to support 7800, you may be in business. :TU: Remeber this is the race section and a race motor point of veiw. Guys running at 6200 and below need not pay attention as this is all overrated for them.
Thanks Bob, Now that's the kind of info I was looking for. The only thing I would worry about is that even though the nailheads came with a forged crank they weren't really designed for high revving power. That may not be an issue but at 8500+ rpm you really have to trust your bottom end. By the way, if I do end up going this route I will order that block with the 4.5" bore size. With the 3.2" stroke out of the 322 that puts me at a 407. 2hp per cube is the goal, so I'll probably need heads flowing around 375-400 cfm to get me there. I'll let you all know what I decide to do. The other option i've been looking at is the short-deck GM racing block. 4.185" bore x 2.75" stroke = one bad 302. With some SB2.2 heads flowing 420cfm and turning 9000+ rpm it has some real power potential. Thanks, Jeremy
Buicks4speed, If you look at the link I posted you can read a bit about that aftermarket block. For a stock 455 block everything you said is true though. And you're right, I don't think losing the low-end torque and making my power up high will be a problem as this motor is going in ~2500 lb car. If anything it might be too much power down low. :3gears: Thanks for the input guys, Jeremy
that's the kind of info I was looking for. :TU: at 8500+ rpm you really have to trust your bottom end. a-yup. i was wondering how much you wanted to twist this. 8,500 is pretty damn serious for a Buick big block. i would think that aftermarket block (whether from Bulldog or the 'upcoming' TA Performance block) should go a long ways towards remedying block strength. as much as it can be anyway. i would think the biggest problem you would have at that point would be the reciprocating weight penalty due to the long rods. i've been kicking the idea around just as a way to meet cube limit rules at our local tracks (that 430 w/322 crank). we'd have em so confused that that right there would be worth it. :grin: i doubt we'll worry about it though. they wouldn't know a BBB if it coated their pants with an inch of tire rubber. and they never do engine tear downs in the lower classes where we'd be running.
You're right about the weight of those long rods, and i've decided to go chevy. That GM block with the 8.2" deck should keep rod length down, I calculate around 5.5" dependant on the pistons of course. Sorry to disappoint guys, I appreciate the help though. Maybe I'll delve into the world of BBB some other time. Jeremy
