# dumb question on connecting rods



## harleybme1970 (Jul 29, 2009)

can i use my pontiac 400 connecting rods on my 455 ? The 400 is a 76 motor and the 455 is a 74


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## ALKYGTO (Mar 29, 2010)

Ditch those stockers and get some Eagle or Scat rods if you've got some extra coin. Stockers will have to be resized and need new bolts, and they are not nearly as strong.


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## geeteeohguy (Feb 2, 2008)

That's mains, but is that rod journal size? I'm in the dark on this one.....


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## jetstang (Nov 5, 2008)

What is the rod length between a 400 and 455? I'm not sure, looks like they are.
Here's an interesting article claiming that bore larger than stroke is better, against all stroker theories. And Rod length of 400 and 455.

Engine Theory by Wallace Racing-Home of Pontiac Powered Firebirds,Trans Ams,and Dragsters
Displacement Rod Length Stroke R/S Inertial Loading Factor Opt. Crank Angle 
Chev. 302 5.700 in. 3.000 in. 1.90 1.263 75.3 
Chev 331 5.820 in. 3.250 in. 1.79 1.280 74.4 
Chrysler 426 6.861 in. 3.750 in. 1.83 1.273 74.7 
Chev 454 6.125 in. 4.000 in. 1.53 1.327 71.9 
Pontiac 317 6.625 in. 3.250 in. 2.04 1.245 76.2 
Pontiac 370 6.625 in. 3.35625 in. 1.86 1.269 75.0 
Pontiac 400 6.625 in. 3.750 in. 1.77 1.283 74.2 
Pontiac 428 6.625 in. 4.000 in. 1.66 1.301 73.2 
Pontiac 303 7.080 in. 2.840 in. 2.49 1.200 78.3 
Pontiac 366 7.080 in. 3.375 in. 2.10 1.283 76.6 
Pontiac 455 6.625 in. 4.210 in. 1.58 1.316 72.4


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## harleybme1970 (Jul 29, 2009)

*wowzerz*

great article. Thanks a ton. I dont understand some of it but i hope i grasped alot, either way im gonna save that for future referance. OK now just to help me understand this better (if you would) the longer stroke is better yes?, and rods from 400-455 have the same length 6.625. and the crank is the same its just the crankshaft revolutions that are different yes? I hope i got that correct.

awesome article


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## ALKYGTO (Mar 29, 2010)

Rods are same length, stroke of crank is longer moving the piston farther down in the bore, increasing volume of the bore. Picture two cans side by side, the 455 "can" would be taller. The 455 will not rev as quick as the short stroke 400, but will create more torque. I hope this helps.

They say there is no substitute for cubic inches, well "they" have never driven a supercharged engine.


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## harleybme1970 (Jul 29, 2009)

thats what i was thinkin ty very much i read that article and felt edumecated lol preciate it .


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## jetstang (Nov 5, 2008)

harleybme1970 said:


> thats what i was thinkin ty very much i read that article and felt edumecated lol preciate it .


Actually, I was confused by the article, and haven't read it all yet. Oversquare, undersquare motors?? Confusing. But, I guess it's the answer to figure out how to make Poncho's run..:cheers


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