Question About LS6 243 Head Work

Slow05CC

Slow05CC

Avery@texas-speed.com
Apr 25, 2014
168
0
0
Round Rock, Tx.
I picked up some low mileage ( 58,000 to be exact ) 243s off a Z06 this weekend and I had a quick question about milling them before I run them over to Texas Speed & Performance for some head work.

I have been told that milling them .030 will retain the factory compression with the 5.3 dished pistons and I just wanted to confirm that before I spend the money milling them and its be wrong and I lose compression. I have also heard you can mill the .035 but it seems to be hit or miss with the intake seating at the correct angle. I guess some people do it and not have issues, then some do it and the intake leaks. Seems like a crap shoot, any light on this?

Another milling question I have: I am in the process of building a 5.3 block with flat top LS1 pistons. Later down the road, would the .030 be too much of a mill for flat tops? I don't want to run into PTV issues! I was looking for some light on this but it seems that guys with flat tops leave the heads alone, and guys with dished pistons mill them. I want flat tops and a mill for the added compression.

I was also looking at a valve job and wasn't sure if a 3, 5, or 7 angle would be the best route? I am sure I could ask TSP when I take the heads up there but I kind of want to have an idea of what is the best options before I get there and get told otherwise then get hit up for a ton of work.

I will be running these heads with a TBSS intake that I got a few weeks ago that is equipped with NNBS Flex Fuel 36 pound injectors

Few pics for reference.

2aafx4l.jpg

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2zdqhx1.jpg


Thanks!
 
Id go with .030 mill, that will get you a lil bit extra compression and would be fine with a 22X/23X 600/600 cam. IIRC Silver04 has a similar size cam in his 4.8 (Flat tops) and has no PTV issues.
 
Silver04 said:
I have flat tops with 243s milled .030 with zero PTV issues. Cam specs 222/226 .604/.604
Click to expand...

What length pushrods are you using with the milled heads? 7.350"? That give me confidence, I don't think I want a cam any bigger then that! My 220r is a monster but it sound too stock for my liking. I was thinking of a vengeance cam, a eps can or a custom patg.
 
push rod length has to be measured for....u gotta take into account the preload u want on the lifters and then you order accordingly, thats the right way to do it. 220r is not much of a monster, imo.
 
2005_Silverado said:
push rod length has to be measured for....u gotta take into account the preload u want on the lifters and then you order accordingly, thats the right way to do it. 220r is not much of a monster, imo.
Click to expand...

I wouldn't say a monster as far as specs or power parse, but with my stall and gears it was a substantial mod. I guess I should rephrase my statement to fun cam! Great DD bumpstick, especially with a 3200 stall and 4.30 gears. It turned my average crew cab into a fun street truck! It just sounds really tame, and with my exhaust set up 99% of people miss the fact that it has a cam!

So when I get around to finishing my iron 5.7 I want a cam that sounds mean, but also spec'ed to give max performance! So most likely a custom grind! So that being said I am sure cam builders can spec a stick that meets my needs but fits without flycutting the pistons. I want to avoid that if all possible


I can run up to Texas Speed and get a pushrod length checker! I can literally walk there if I wanted too
 
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I have a brand new set of Manton PR's that are 7.375 that I'm pretty sure I can't use as we changed some things last minute on my build.
 
Got my heads milled yesterday and this is the results. I cut .030 off them. I think they look pretty good, and the edges are sharper then my kershaw knives haha

71236f.jpg
 
When I did mine I had them milled .032.
PTV issues you should be fine just measure for PR length.

I had my 799s milled, bowl blended, short turn radius slightly worked, back cut the valves...ect the cheap and easy work. They picked up 24CFM on the flow bench over factory.
I also went with an EPS cam which uses a smaller OD core so once ground and using a milled head my PR length came to using the factory 7.4 length.

My specs were 224/232 609 607 111 in and iron 5.3 stock bottom spun to 6800.
 
Samuel6731 said:
When I did mine I had them milled .032.
PTV issues you should be fine just measure for PR length.

I had my 799s milled, bowl blended, short turn radius slightly worked, back cut the valves...ect the cheap and easy work. They picked up 24CFM on the flow bench over factory.
I also went with an EPS cam which uses a smaller OD core so once ground and using a milled head my PR length came to using the factory 7.4 length.

My specs were 224/232 609 607 111 in and iron 5.3 stock bottom spun to 6800.
Click to expand...

I thought about going with .032 but figured that small amount wouldn't hurt or help so I went with the .030! My original plan was to slap them on my 5.3 with the TBSS intake, a 224/228 TSP cam, and stuffing some 4.8 pistons in it then retuning it... But I may be trading my centerlines for a LQ4 this weekend so if that happens the heads will ride on top on a 370!
 
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