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Main and rod bearings for 500hp


Nov 21, 2018
Hello TBs,

I'm putting together a bottom end with Yoshifab connecting rods and ARP main studs.

Target crankshaft HP is 450-460 (looking for a 400ish at the wheels).

The car is a drift missile and spends a lot of time in the high revs and being abused as you do at drift days.

I have a set of Glyco main and rod bearings from FCP:

The shop that puts my bottom end together planted a doubt in my mind making me think maybe I need some reinforced/racing main and/or rod bearings instead? They specifically suggest ACL.

I tried to look for a set of ACLs but found only rod bearings:

At first I was going to ask for help with looking for a set of reinforced ACL main bearings - but then decided to ask if these are even required?

Thank you for your wisdom!
I've had fine results from FM mains, and clevite 77 rod bearings.

actually the mains may be glyco not FM. I'll have to look through the pics.
I haven't had a girdle on any of mine, but that's probably not a bad idea. the main thing to keep in mind with that kind of abuse is to be soft on the tune and ensure you have more than enough cooling (for both coolant and oil and transmission fluid probably as well)
Thank you!!

Excuse my ignorance - but what is a girdle? Is that a specific product?

Also, seems that I'll settle for "Glyco" (these are OEM grade I believe) main bearings and "ACL Race" reinforced conrod bearings.

Cooling wise I have a do88 radiator and a Chinesium engine oil cooler for which I'm running an always-ON (with a switch) OEM radiator vent in the high speed setting. This seems to manage temps quite well in the 300whp range.

I may move the oil rad aside and give it a dedicated vent though. Cause right now it, and the steering fluid rad, just sit stacked on the intercooler which is a do88 unit that does an amazing job so far.

It gets really hot here in the summer months. Jul-Aug are basically no-no for any motor sports activity. But even outside these months the cars need all the help they can get for cooling.

Happy new year everyone!!
A block girdle is a big steel plate that bolts to the block through the main bolts to stiffen the block and prevent it from twisting around the crank. Think of chassis braces for the engine block
Why would you need those? Overboost racing does a complete 600hp "workhorse" redblock with cast pistons. Of course that's with e85.
OE pistons use massive rings that don't seal well at higher revs, and then you get a lot of blow by. While you can make the power levels, it's all at a compromise somewhere else when using stock-type pistons.
Forged pistons also give you a slight safety margin when making big power. You can still destroy them is a matter of seconds though, but usually the piston will hand together well enough to save the block/rods/crank.