RabidStreetRacer

iTrader: (1)

So I took the heads to the shop and the guy was very nice and willing to hook me up with a great price. He is going to remove the 2 sheered off exhaust bolts, clean the heads, install new valve seals and some LS6 springs I have. Also the guy is willing to mill the heads all for $200.

I need to let him know tomorrow how much to mill.

I am going with the Comp Cams Thumpr cam. Specs are:
Cam Style Hydraulic roller tappet
Basic Operating RPM Range 2,000-6,400
Intake Duration at 050 inch Lift 219
Exhaust Duration at 050 inch Lift 233
Duration at 050 inch Lift 219 int./233 exh.
Advertised Intake Duration 275
Advertised Exhaust Duration 295
Advertised Duration 275 int./290 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.553 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio 0.536 in.
Valve Lift with Factory Rocker Arm Ratio 0.553 int./0.536 exh.
Lobe Separation (degrees) 109

I need to know what you guys recommend for how much to mill and what do I do for push rod length and do I need to worry about accessory alignment?

Engine Mods:
LM7, factory short block
Milled heads? 862 heads With LS6 Springs
Thumpr Cam
2" Primary LT headers, 3" exhaust with duel SLP Loudmouth mufflers
Edelbrock Performer RPM duel plane intake
Holley 750 cfm carb probably will do E85 conversion
MSD 6LS

99fbodyTA

Damn I was reading the cam specs when I noticed the lsa. Lope much?

99fbodyTA

And where did you get 200 mill work from

RabidStreetRacer

iTrader: (1)

http://www.youtube.com/watch?v=NeQ0jk-7Uzc
Thats what it will sound like, beautiful!

I am a Firefighter/Paramedic and I stopped by a local shop while I was on duty so the guy was very nice and said he would take care of me.

baxsom

iTrader: (6)

In a C3 forum when I was looking for a cam for my 454 I was told get a thumper cam and sound like you have power or get a good cam and actually have it.

RabidStreetRacer

iTrader: (1)

This cam is Comps 2nd recommended cam for my application. I don't want crazy power. This cam works great for a carb application. Also the cam works with LS6 springs which I already have. And it will work with a stock stall. I am looking for around 400hp so this will be right there.

99fbodyTA

cool. i was wondering because i have a set of stock ls1 heads with patriot dual gold valve springs already installed, and was thinking of selling them, but if i can find someone to mill them for that, just might do it. cam sounds great as well

99fbodyTA

as far as the pushrod length, talk to the guys at your machine shop they may be able to tell you better than i could honestly. i went with texas speed chrome moly's

RabidStreetRacer

iTrader: (1)

The guy at the machine shop told me to find out what I wanted the heads milled to based on other peoples experience. He said he has been doing alot of LS engines lately but he just does machine work and does not build the engines.

RabidStreetRacer

iTrader: (1)

Comp Cam's Dyno simulator with this cam and setup estimates the following:
Peak HP: 449@6000rpm
Peak TQ: 451@4500
Not bad considering I would be happy with 400.

RabidStreetRacer

iTrader: (1)

I should mention that I would like to have around 11 to 1 CR

litle88

iTrader: (20)

59-60cc's and you'd be at 11-11.5 compression IIRC. I'd do it.

RabidStreetRacer

iTrader: (1)

I'm 100% down to do it, just don't know how to find out before I mill the heads if I will have a piston to valve clearance issue? Also, how hard will it be to get push rods?

batboy

iTrader: (6)

I posted in your other thread in the truck forum. You're not gonna get 11:1 with those stock dished pistons. With flattop pistons, yeah. But, you listed the short block as being factory stock. The 5.3 heads are already at 61cc compression chambers. You can't mill them too much without running into piston to valve clearance problems. Generally, 59cc chambers are about as far as you want to go, maybe 58cc at most. The rule of thumb is 1cc for every .006" milled. The most I would personally mill is .015". At least that cam you listed has modest lift. Unless you change pistons, you are going to be at about 10:1.

RabidStreetRacer

iTrader: (1)

Thanks for your response, this is the answer I was looking for. Someone who knows their stuff. Other sites people were telling me to go 0.03 but gave no explanation.

batboy

iTrader: (6)

Milling .030" works with LS6 or LS1 heads, but not so much with 5.3 heads.

LS1 heads = 66cc
LS6 heads = 64cc
5.3 heads = 61cc

ZQ8LS1

iTrader: (3)

Not to jack this thread but I have a L33 but do not have the 799 heads that it came with...I have a set of 853 heads that have to be milled to eliminate some surface scars.

How much would you remove ?? Stockish daily driver with a tune.