How strong is my setup?

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C

Chrippa

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Hi!

I recently got some info on the engine that sits in my car that i bought last year!
The engine is a 340 stroked to 416 with mopars 4.0" stroke crank. The crank has been cryonized (spelling?), what is this and what does it do?
The rods are stock rods that have been shot peened and polished.
The block is a standard 340 bored .030 i think, the pistons are Hughes Engines part # 2020+070. Compression height is 1.377; 0 deck clearance;
effective dome volume is -26.5 cc's.Weight is 610 grams with pin. Piston ring set is also Hughes Engines part # 2114.
The cam is comp cams V 9215 Part # 2-000-5, with @.50 239 intake and @50 242 exhaust.
Lift with 1.5 roller rockers:
534 intake
540 exhaust

Im just wondering how much this setup can take and how safe it is to ride with stock rods? I have been given different opinoins on shot peened rods, some say they are stronger than eagle rods and some say they arent?
And how much rev would this engine stand, i have heard around 6500rpm?

The car sees both strip and street use, but mostly street as we dont have so many tracs here in Sweden ;)

Cheers all and thank you for any answers!
Chris
 
What heads, intake, carb and exhaust do you have? Assuming they have ARP or some aftermarket high strength rod bolts they are probably as good/or bad as any other SB rod unless you get in the $2k range. 6500rpm for a long stroke 416 is pushing it, I'd shift @ 5800-6K in 1st and 2nd and let it run out in 3rd. I have a 3.79 stroke and cross the finish line @ 6700 - works good.
 
388dart said:
What heads, intake, carb and exhaust do you have? Assuming they have ARP or some aftermarket high strength rod bolts they are probably as good/or bad as any other SB rod unless you get in the $2k range. 6500rpm for a long stroke 416 is pushing it, I'd shift @ 5800-6K in 1st and 2nd and let it run out in 3rd. I have a 3.79 stroke and cross the finish line @ 6700 - works good.
Click to expand...


Heads are Mopar performance stage1 alu heads that have been converted from closed to open chamber. Intake is Mopars M1 single plane, carb is a Holley 750 and exhaust is TTi step headers and a 2½" system with h-pipe.

The rods have ARP bolts in them. But how about if i change to say Eagles ESP H-Beam rods that they say will hold up to 700 hp and 7500 rpm? Would that give any big gains in strenght or would it be throwing money away ?
 
As far as rpms, the MP crank will spin 6500 with no problems. The block on the other hand, or more precisely the main caps, may not like it much. Nor will the stock rods. With that cam and what I'm guessing are some form of Commando heads, I'd think peak hp is down around 56-5800. So you dont need to rev it. The problem is that crank accelerates that piston and rod much faster than a stock 3.31 thru the same cycle. You run the risk of poulling the small end right off the rod if it's revved too high. As far as being as good as Eagles..I'd say a properly prepped set of stock rods, with shot peening, is the equal to any $269 set of SIR rods. The H beams are a bit stronger, but can tend to be heavier than a factory rod. This is why the majority of 4" stroker buildups use H beam rods or good I beams, and forged pistons vs. hypereutectic. The piston acceleration is just too fast for stock rods and cheap pistons.
 
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