I am rebuilding a ls1 stock bore and stock heads with a polluter cam from tick. I've had the pistons flycut and am debating using the stock 853 heads or switching to 5.3 heads with bigger valves. Which would be better?

It's an a4 with a 4k stall stock weight

 

I'd say go for the 5.3 heads in a heartbeat, but get them ported and milled a hair too while your at it.
If your not going to have the 5.3s ported is just stick with the 853s. Also if/when you pull your heads go ahead and drop in new lifters and ls2 lifter trays.

 

I'm doing a complete rebuild with new lifters timing chain oil pump bearings and rings I just want to se if it's worth picking up 5.3 heads for cheap

 

If your getting a good price on them and pulling your heads anyway, then why not....I just couldn't justify breaking a good running motor opened and paying for all the fluids and gaskets to drop unported heads on, but if you are rebuilding it, then I'd do it.
They will bump your compression up a hair, and the bigger valves will let it breath better so you should see some gains.

 

I would get the 5.3 heads if they were a decent price and then get them ported, maybe milled slightly.

 

If I do get them I'm doing minimal work to them. Probably just getting new valves put in and putting them on the engine

 

That doesn't make sense to me. If you're swapping heads, might as well make it worth the effort. And unless you are rebuilding the shortblock with new bearings and rings, you shouldn't pull the heads just to replace the lifters, unless you have a lot of miles on the car.

853s and 5.3s flow similar - just the 5.3s bump the compression a bit. And you can't just stuff bigger valves in there. You need a valve job as well.

 

The motor is out of the car. My motor melted a piston. Got new stock pistons and rehoned the block. Putting it back together. Ik it will need a valve job I just am not going to mill or port them if I go through with it

 

Sorry for the confusion

 

What size valves were you thinking?

 

Don't do that.

If you are not going to get the 5.3 heads fully ported you're wasting time. Get your stock ones milled and a valve job instead.

 

Eff my budget. Im just going to buy a set of ported heads lol thanks for the advice

 

LOL.

That's the spirit!

 

Good Idea!!

 

My buddy just told me about some so I am just going to do that. Lol it'll push my build back a month but Ohwell haha

 

Hate to do it, but sometimes it is worth it lol I planned on having my car done and ready by Spring Carlisle...last year but it is still sitting in my garage lol oh well, it will be worth the weight!

 

So what heads are you going with OP?

 

+1^^
Curious myself..

 

Fully Ported 862s with a 2.02 intake Idk if theyre milled or not

 

I run the 862 castings as well. They were done by Texas Speed so I don't know all the details on them. They make some good power though