SBC 350, 600 horse, connecting rod set

[Dragsinger]

Racers and builders,

The engine in question is 350 SBC of about 575 horses with an upper RPM range of about 7300. A trailered, drag race engine with 12:1 compression on Methanol.

The mainstream market has quality rods with 7/16 bolts and premium features, and they are priced in the $550.00 - $600.00 wholesale range. In the past, that has been my rod of choice.

In addition, I see Scat rods in the $350.00 - $375.00 range that claims to be sufficient for the 600 horse range.

Do any of you have experience with the lower-priced rods?

[cgarb]

Are you talking about the Scat Pro Comp I beam rods? If so I have had good luck using the same type rod the Eagle FSI series in engines very similar to yours. I built 2 355's with those rods that are in the 500hp range. One runs 9.90's in a Mazda RX7 on methanol and it has like 3 or 4 seasons of bracket racing on it now with no issues and the other has not made it to the track yet, but I ran it on the run stand to break the camshaft in. Only problems I had with them was a couple of the small ends were a little on the tight side. A few strokes on the hone and the pins went through nice then. I bought another set for a 347 ford I have not had out of the box yet.

[KnightEngines]

I've used the pro I beams at 630hp, 7800rpm, but I was not comfortable doing so.
They held up ok but I replaced them with H beams at 1st freshen.
I consider the good I beams suitable for up to 550hp/7000rpm or a tad more.

Put the good rods in!

[mag2555]

Since your a racer and-all of racers always end up building for increasing power levels down the road, then it pays now to shell out the money for better Rods!

Just look at the future cost if you where to do the up grade to next season or whatever.

1) better Rods, likely to cost more later.

2) rebalance cost.

3) gasket set .

4) your time.

With the average balance job these days costing $150 your better off now putting those funds into stronger Rods!

[houser45]

Scat H beam w/8740 std bolts would be cheap option #1

Compstar H beams would be the next step up #2

Dyers, Carillo, Oliver,Crower would be the top level #3


Take into account How light of a crankshaft bobwieght you will be close too. If you are using a magnum xl Callies with a 1720 bobweight you will not want to use the scat/eagle rods. If its a standard weight crankshaft the heavy stuff will balance easy.

[cad]

Hi Larry,
I ran the SCAT i-beam rods in my 385 for the past 6 years. I put 175-225 runs per season shifting at 7200. I had the engine in my 68, and then put the engine into the S-10. NO issues. 13:1, AFR 220s, glide, 6000 converter....

Clark D

[panic]

The projected HP level is far less important than the peak RPM (inertial load on the rod varies as the RPM^2; 7,000 > 8,000 is not +14.3% but +30.6%), and reciprocating weight.

[Mark O'Neal]

That Scat I-Beam is 4340 and has a 7/16 bolt in 8740, 2000, or L-19....and it's pretty light.

I'd run them without a second thought.

[Lizardracing]

Been using the Scat Pro series I beams with 7/16" bolts in circle track stuff for a long while. No problems other than a couple out of round a few tenths after 50 nights at 7500, 421ci engine. Fixed that and it's still going.

Even broke a piston one night at 7500 and the 6th rod wrapped it self around the 7th rod. The big end of No 6 was still attached to the crank so I had to use a cut off wheel to remove it. Crank and 2 new rods and it's still going.



Lighter pistons are always better for the rods.

[Krooser]

My dirt Mopar motor had bushed 340 rods in it when I bought it. The engine grenaded thru no fault of the rods.

I collected another set of OEM 340 rods and had them resized and new ARP bolts installed. I figured they were plenty good for my 6500 rpm/575-600 HP deal.

Then I found a used set of Crower I-beams for $500.00. Bought those, had to have the small end opened up from Chevy size and installed new bolts. The weight was fine. Now I fell OK running this deal at about 7500 rpm. I hope I'm right!!!

[runawy9]

What is the pin diameter for the 340 pistons?

[Walter R. Malik]

Horsepower output has almost nothing to do with the capability of any connecting rod.
RPM, piston speed and reciprocating weight have the main things to do with rod strength capability.

[DCal]

What is the pin diameter for the 340 pistons?

.984 is stock

[1980RS]

For the next 406 build I picked up a set of Manley I-beam 6" rods with 7/16" cap screw bolts.