phughes69

I rebuilt my starboard engine 2 years ago and I am getting ready to do my port one now. When I redid the starboard engine, I used L2453F speedpro forged pressed pin dished pistons and I want to use these same pistons to keep the compression ratios in the motors the same. I wanted low compression for the turbos. I had the stock rods (LS6) honed and new ARP rod bolts and I had the crank ground .10.

This is not a high HP high revving engine. I use a flat tappet turbo spec cam in it and 188 heads on it. My rpm are about 5400-5600 and I estimate my HP to be about 600-to 750 (depending on how much boost I want)
The long blocks are 370 HP 1980 Mark IV's (LS6 spec forged crank, 7/16 forged rods, rectangular iron heads)

Now my question is is it worth it to have the stock rods honed and new rod bolts on the port engine or is it better the get a new set from summit. A new set from summit is: Scat I beam 7/16 bolts- $271 or Eagle SIR I-Beam- $299.

MILD THUNDER

iTrader: (3)

I'd go with the new rods bud. My personal opinion is to go with new H beam style rods from eagle, scat, etc, over the I beams. They aren't much more money.

You may be able to get 100 bucks out of your old rods on fleabay if in good shape.

Your turbo engines are cool old school man !

MILD THUNDER

iTrader: (3)

Post some pics of those things

sutphen 30

I'd go w/ new rods and have the whole thing balanced.

mike tkach

iTrader: (3)

mercury marine went to an h beam rod in the hp500&525 .you can buy a set of scat or eagle h beam rods with 8740 bolts for not much more than it cost to rebuild the gm rods with new arp bolts and they are way stronger than the gm rods.as mentioned earlier get the assembly balanced.

airjunky

iTrader: (2)

Normally i would vote 7/16 for most 5500 rpm but when you almost double the power with a turbo upgrade ,and then post pics
it doesnt take much for gm to change the balance for cranks with the same casting number in a stock app so dont skimp there either

getrdunn

iTrader: (7)

I have mixed feelings on this however feel either way you'd be fine assuming you'd have your machine shop ck out your rods and resize if necessary. I knew an old time engine builder who always preferred to reuse rods. Only of course after being thourgherly checked out mic,hone,resize. His reasoning was they were done being stretched etc. He had an unfortunate experience early on with a new set with a defective one that ultimately grenaded the engine in a sbc.

Not saying to use that advice for determining your decision however just thought I'd throw it out there. It always kinda of made since. Once again I'm not trying to say it's a better route to go. It's simply sharing an experience that was shared with me many many years ago. In regards to the hp and torque I've run the GM rods up to 800 hp with no issues what so ever. That was well balanced and under 6,500 rpm.

MILD THUNDER

iTrader: (3)

The GM 7/16 rods were a good rod, for their day. However. By the time you magnuflux them, resize them, new bolts, ( I wouldnt reuse 30 year old bolts in a turbo marine engine) maybe bush them, shotpeen, etc, you'll still have an old 4130 Forging, with thru bolts rather than cap screws, which have seen millions of cycles, that simply arent' as capable/strong as a modern 4340 Forging already setup for floating pins, with good bolts, for the same or similar cost.

Scat and I think eagle, make an I beam rod, with or without capscrew style bolts, and 5140 or 4340 forging. If you are going that route, I'd spend the couple extra dollars, for the 4340 capscrew rod.