ATTN : Expert engine builders. Question.........

[speedzone]

I am rebuilding the 408 Cleveland stroker for my Pantera...........forged crank, rods, 4 bolt mains, 11.5:1 CR, CHI heads, and 252 duration @ .050 roller cam. Should be + - 600 HP. The pantera uses a different oil pan and extended pump pickup that requires a special windage tray. This also requires a "towered" style main bolt to mount the tray and pickup on 4 of the inner main bolt locations. I purchased a set of new main bolts from ARP, but in the other aformentioned holes I had to use the non ARP towered bolts (which are actually a common main bolt in Chevy truck big blocks). So basically I have mixed and matched and I'm using the towered bolts in the 4 needed locations and the rest are the ARP. The shop that did the machine work is performance oriented and very well known and respected in my area................and they have assured me that this will not be a problem, being that the thread and reach of all the bolts are the same. Well, now that I am getting closer to dropping the motor in, I am having nitemares of different clamping forces and a wasted crank and or bearings because of it. Can any of you experts chime in with your expertise or opinions?

[camcojb]

have you called ARP to see if they have them, I bet they do. By "towered" I'm picturing a normal looking bolt or stud on the bottom narrowing to a smaller thread on top to hold the windage tray, uses two different bolts and washers.

Something like this on the left:

http://static.summitracing.com/global/images/prod/large/arp-156-5401_w.jpg
Jody

[speedzone]

Yes, ARP has towered studs, but not the bolts. I'm running bolts. Thanks.

[camcojb]

Yes, ARP has towered studs, but not the bolts. I'm running bolts. Thanks.

ah, missed the bolts parts, I always think studs with ARP. I think you'd be fine in that case.

Jody

[deuce_454]

the clamping force inst dictated by the mfg of the bolt but by its physical properties, angle of thread, diameter of thread, surface friction (if they both are lobricated it will be same) and the friction under the bolt head when torquing...

so unless they are torque to yield (which main bolts are not) the clamping force will be the same if you torque them simmilarly..... so sleep tight and dont worry about it...