Quote:
Originally Posted by RAMAIR RICK
Thanks Tom for sharing your engineering wisdom. With all of the different firing order options out there today, from an engine dynamics/performance standpoint, is there one firing order that is better then all the other V8's??? and if so is it worth going after??? Say the Ford/LS engine firing order or the 4/7 swap. Thanks in advance
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The ORIGINAL FORD "late" 302 and 351W used the Firing order known as the LS firing order (for the GM guys). Ford went with this firing order because it eliminated the "Double Hit" on the #1 and #2 Main caps with The right front cylinder firing and then the left front cylinder firing. By doing this the block and crank saw a lot less stress vs using the GM firing order.
On a Factory Pontiac block, in my mind well worth the effort.
With a All Pontiac Block that has had the front bulkhead strengthened over the years and steel main caps on all 5 positions, maybe not such a big deal on the block but the crank still sees the hit on two crank journals for the 6 then 5 and 4 then 3 with the LS firing order and 4 then 3 and 6 then 5 with the Pontiac firing order.
So to repeat again, the benefit is on the front main and the second main that see all of the normal stress in a normal pontiac.
I have inspected Factory 455 4-Bolt main blocks with cast caps where the #2 main was broken completely around the inner bolts, the thrust cap was broken 3/4 of the way from the block surface moving toward the windage tray, and 1/2 broken on the #3 cap, again the crack started at the block surface and was moving toward the windage tray.
So the #2 main cap sees a lot of stress with the factory Pontiac firing order.
If you have a supercharger belt applying force on the crank snout it is even worse.
Tom V.