moekluse

iTrader: (2)

I don't want to weld up my current heads, so I'm ready to drop some money for some nice heads. What's the smallest chamber/highest flowing heads that will bolt up to a 5.3? Would also like them to be cnc ported, how about a 58cc tsp prc heads? How about mms?

KCS

iTrader: (20)

You can probably do any ported 5.3L head and mill the hell out of them. Depending on how much, you may need to mill the intake faces to fix the port alignment to the manifold.

moekluse

iTrader: (2)

I'd rather just go ahead and buy some nice heads, and not worry about machining and turn around time. (My machine shop guy does awesome work but is super super busy)

JoeNova

This has come up 3 or 4 times in the last few weeks. Most places that will port factory castings will also fill the chambers and machine them to smaller size for $200/head. You can get ~52cc chambers out of a 5.3 pretty easily and not have to mill them at all.

moekluse

iTrader: (2)

well, I have 317, so I'd have to pickup 5.3 heads and machine, I'd rather just get new ones. What do you guys recommend?

JoeNova

I'd recommend finding a vendor that will fill chambers and ordering heads from them lol.

moekluse

iTrader: (2)

No one would go out and buy some nice, brand new heads? I'd honestly rather go that route. I don't really have a low budget so I'm willing to fork out $$ for the best

JoeNova

I'm pretty anti-aftermarket when it comes to buying head castings (in most situations), so I can't really recommend the best head. Paying a premium for flow numbers when you're only feeding 5.3L is pretty unnecessary. CNC ported stock castings can flow 300 CFM which is more than enough for most 5.3s.

moekluse

iTrader: (2)

I'm really wanting some aftermarket heads, I know I can get away with gm casting heads, but I'd rather have some nice ones

KCS

iTrader: (20)

Not for a 5.3l...but it's your money.

JoeNova

Your engine doesn't care that they are 'nice' ones at all.
Just curious, why did you ditch the turbo project?

moekluse

iTrader: (2)

oh, I'm still going turbo, but smaller, only shooting for 700hp max. I took you're advise, I'm trying to bring some compression back. I diched the 1000hp drag car for a 700hp daily driver. It's a 78 transam protouring car. I just wanted to bring it up to 9.5:1 for that low down torque, I got rid of that Howard's cam and will spec one after heads, turbo, etc are planned.

NAVYBLUE210

Best flowing small bore/small valve, aftermarket heads that I know of
MMS 205 5.3s. Give Tony a call or Email. Certainly not the most cost
efficient way to reach your goal but I certainly understand
Stubborn, and resemble that remark. Check out my build for proof
LOL.

moekluse

iTrader: (2)

Just wondering but how much can you mill/weld chambers on a 317? What's the smallest I can get the chambers?

Quick Ranger

iTrader: (2)

Trick Flow actually makes a head just for the 5.3. I believe they come at 58cc.

JoeNova

Why not swap for 243 or 799 heads?
A few % more flow than the 317s and a much smaller chamber.

moekluse

iTrader: (2)

is there a place I can get them from new or remanufactured? None for sale in my area

JoeNova

Powell Automotive sells updated 243 castings.
They flow 10% more than the OEM versions.

Otherwise, check craigslist or the classifieds. They're all over the facebook LSX groups.

MuhThugga

A big part of compression with the 5.3 is what piston you have. Are you using a dished or flattop piston?

Since you don't mind buying an aftermarket head, look at the PRC ported 5.3 heads that Texas Speed offers. They'll have the smaller 61cc chambers. Those heads, combined with a flattop piston and a GM head gasket, should bring you to around 10.5:1. Going to a .040" head gasket and/or having the heads milled will bring you closer to 11:1, but I would advise measuring beforehand to ensure how much further you can go.

moekluse

iTrader: (2)

I have a dished wiseco -10cc piston. I know that doesn't help me bring compression up but it'll bring it up to 9.3:1 which should get the job done