Ok I am building an N/A LQ4 up to a 370. It is a DD and in a 3/4ton truck. I am installing PRC 2.5 5.3l heads, a 224r cam .581" lift, speed pro dished 4.03 pistons, along with all of the other odds and ends required of a rebuild. I am wondering if it is worth the money to buy new rods or just throw some ARP bolts in my stock set. I am under a tight budget and would rather go the ARP route but I do not want to cheap out on a crucial part. I feel with the modest build I am doing I should be fine but I would like some input anyways. Thanks

 

The powdered metal rods are typically a weak point, so it would be wise to upgrade. What compression are you aiming for with this engine? If your dished pistons are going to drop it down, you'd be better off budget-wise to stick with the 317s. You'll lose quench with those dishes, and for no reason. Unless you're sticking to high CR...

 

I would think the stockers would be just fine. Alot of guys on here running them and turning high rpms with them. I would just slap some arp bolts in them and run them or get a set of the LS2 rods which are floating and a little stronger.

 

Why would I be better of with stock heads? My pistons will not be dropping the compression, my truck comes with dished pistons stock, it is not the LQ9. I have already purchased the PRC heads and I do not plan on getting rid of them.

 

See that is kinda what I was thinking and it is not like I am building some high strung motor I think it is a pretty basic rebuild with a few mild mods.

 

My understanding was you wanted to save money. You decrease quench with a bigger dish. You could maintain quench without the use of dished pistons with the 317s, and assuming the same CR, you'd probably make the same power for less money. Since you are staying NA, quench makes more difference, as opposed to using forced induction. But if you already have the heads....disregard. lol

 

OK I do have another question though. I am going with the speed pro 4.03 pistons and they need the stock 6.098 rod length, and I have found some but I see a lot of 6.125" rods. Now can I use these longer rods? It may be a dumb question but I am not sure.

 

No, your pistons will stick up too high
(too far past the deck). Also need to watch the wrist pin size too.