badmfkr

iTrader: (4)

Thinking of having my 853 heads ported, polished and changing valve sizes w/ stainless steel valves intake 2.02 exhaust 1.57 can this valve upgrade be done w/ hand porting?

also thinking about milling these heads for a 11.0:1 compression ratio (I only use pump gas).

I also would like thoughts on port matching the LS6 intake manifold is this just done on the bottom? & is it recommended?

all this for a 346CI stock LS1 w/ tame cam, tame TC & Lts. just looking for a fast fun reliable daily driver.

I'm new and just asking for advice car is rarely drag raced.

Thanks

KONG

iTrader: (4)

It really isnt a bad way to go if you dont have the money for aftermarket heads. A local guy in VA Beach, VA has a ported set on his T/A and a cheater cam. He dyno'd 423/378. Its a six-speed car but the point is they are capable of good power when done right.

bshell

iTrader: (24)

Not sure if you meant me or not. I also have a set of stage II ported 853s (stage II = bigger valves, usually 2.02 / 1.57), and a 230/224 cam. My heads are unmilled and I'm using stock head gaskets. I put down 423hp / 371tq. Be careful with milling the heads and running larger valves as your ptv clearance is quite a bit closer to begin with.

StripedZebra

iTrader: (6)

Bshell, who ported yours and about how much it run you?

bshell

iTrader: (24)

FFHP - Force Fed High Performance. Now bankrupt. The heads were on sale and were less than $1k and came assembled with 2.02/1.57 valves, PP Gold dual springs, new stock head bolts and gaskets. Many of the sponsors on the right can offer similar deals on better heads than I've got. If I were to do it over again, I wouldn't go with bigger valves at all. I'd instead go with a set of ls6 style ported heads and mill them to boost cr. By the way, the current ls6 style port jobs flow just as much as my heads, but have way better compression and mid lift flow!

The Alchemist

iTrader: (19)

Well, after measuring my heads, and a stock set of 853's, I found out that my heads were milled roughly 0.036" which bumps up my compression to about 10.9:1 using the stock 0.053 graphite gaskets. I wanted to run a 0.040 gasket to cut down my quench, but that's not going to happen at this point in time. I'm going to play it safe and order as set of 0.051" cometics and call it a day.

Be careful milling too much because of PtoV clearance issues.

badmfkr

iTrader: (4)

must the stock 853 heads be CNC ported to use the bigger valves?

or can they be handported for the valve upgrade?

PTV I'm assumming it means piston to valve clearance?

my cam only has a 551. lift. is lift what makes it close if so will this be an issuse w/ my 551. lift.

I also planned to use stock GM head gaskets.

on the LS6 heads how much milling would you have do to acheive what compression?

Thanks for advice

bshell

iTrader: (24)

I'd be a little weary of hand ported heads. Unless the porter has a lot of experience with lsx heads and has a flowbench to test the work on. Its real easy to overport and kill flow. With cnc'd heads you'll have a tested, proven setup. Take a look at the sponsor list, there are a number of stock casting cnc'd heads available for $1k or less.

Cam lift is not an indicator of piston to valve clearance issues. Max lift occurs near bottom dead center. You need to look at int/exh duration and lsa. If you are keeping the cam in your sig and running stock gaskets, you should be fine.

Studytime

iTrader: (15)

They don't have to be CNC ported, they can be hand ported. Yes, PTV is piston-to-valve clearance. Duration is more important than cam lift when figuring PTV clearance. Peak lift doesn't occur at top dead center. The GM MLS head gaskets are awesome and will work well for you. If you mill those LS6 heads around .018", that'll get you around a 62cc chamber for right near 11:1 compression.

Ben T.

Studytime

iTrader: (15)

Have you personally seen any of those $1K CNC LS6 heads? I've been doing some head porting for a while I'm not convinced those are the best option, with their nearly 240cc intake runners. I'd rather take a nice hand ported LSx casting with a 220cc runner over a CNC LS6 head with a 237cc runner, especially if both flow the same... atleast for my builds.

Ben T.

bshell

iTrader: (24)

Yes, definitely take the one with the smaller port and the same flow. Port velocity is what I was trying to get across in the stock valve size vs larger valve size.

Studytime

iTrader: (15)

Well put bshell. Also, impressive results from your TR230 cam with a set of heads.

Ben T.

bshell

iTrader: (24)

Thanks Studytime, I was impressed as well. I know my heads were overported (cnc'd 853s by the way) in that they have 247cc intake ports and 68cc chambers. I also have a bit of a parts mismatch with the cam in that I have a much better flowing intake cycle vs exhaust right now.

Studytime

iTrader: (15)

I'd say that 90/90 still isn't idea for an LS1. A good single plane intake would be a way better, so having a reverse split still doesn't sound like a bad idea.

Even Thunder's new cam the TRak cam is a reverse split at around .150" and above if I'm not mistaken. Compare duration of the LSk intake and the TR exhaust lobe and it's evident. There are people putting up plenty of power with it and a 90/90, so I really don't think your TR230 is a horrible choice with the 90/90.

Ben T.

Randy WS6

iTrader: (69)

I have a set of #853 5.3 heads, with Farra stainless steel 2.02" int and 1.57 int. valves and a three angle valve job ,shaved .030" and hand ported & polished and the chambers are polished also, and has Patriot gold springs and titanium retainers, I had these on my 347cid. and perfect for it. they have been freshened up ready to go. if you know any body needing this heads ill take 700.00 + shipping

The Alchemist

iTrader: (19)

Hey Randy, what thickness head gasket were you running with the milled heads?

Randy WS6

iTrader: (69)

.042 but i had Ross pistons in at the time with 3cc valve releafs