STL94LT1

What to do? I can buy a brand new set of LT4 heads and intake for around $1400, or should I just have my LT1 heads/intake ported?

Ruby6spd

Port the existing one's, you can get a lot more power from the ported LT1 than the stock LT4. Ported vs Ported the LT4 will produce more power, but if your not going to port the LT4 the ported LT1 would be better..


[Modified by Ruby6spd, 1:40 PM 7/2/2002]

ConeKLR

What's the flow rate of ported LT1 heads compared to stock LT4 heads.
LT4 heads flow 220?
:confused:

RichS

My ported 95LT1 heads with 2:00/1.56 valves flowed @ 28":
-Lift---intake---exhaust
.200---201.4---136
.300---237.0---175
.400---255.4---187
.500---277.6---191
I can't find the sheet for my LT4 heads that still have the stock vaves and are ported also. I think they only flowed a bit better that the LT1 set.

93Polo

http://www.fierolt1.com/lt1_lt4_headflow.htm compares head flow between stock and ported LT1/LT4 heads. Keep in mind all flow benches will vary, and velocity is another big factor.

silver & red CE

Rather than blow money on the LT4 heads and manifold, I'd purchase a set of AFR's or port the LT1 heads.

Eric

93Blackrose

I've also been kicking around the idea of using LT4 heads/intake instead of porting my stock LT1 heads. But after endless research, I have decided to get my LT1 heads CNC ported. Porting your stock LT1 heads is the way to go for the most power.

joe-red78

Who does the porting and how much does it cost?

Thanks,
Joe

Bob Mosaic

I am curious as to how much velocity and better induction efficiency the .100 raised runner of the LT4 adds to the poer figures. The vortec to std SBC differance is worth tons.
Cheers,
Robert


[Modified by Bob Mosaic, 8:51 PM 7/2/2002]

93Blackrose

joe-red78

I've found two porters with good reputations. They are:

CNC Cylinder Heads http://cncheads.com
Trevor Johnson http://www.tjcylinderheads.com

Pricing is $1300-1500.

STL94LT1

Thanks for the comments guys, looks like I will be working with my LT1 heads/intake.

93Polo

Speed Demon was working with Gallant. Gallant is one of the best porters in the business.

STL94LT1

Has anyone had any dealings with these guys? They say they can use the stock valves and still get really good flow numbers.

Half Fast

They did the work on my heads. Don't go by their web site, call them up and talk to Pete. Let them know what you're doing and what you want. They can do anything you need. They do very good work, a lot of the big name tuners use them. If you're staying with stock displacement velocity is much more important than port volume. :chevy

STL94LT1

Thanks Half Fast, I will call them Friday.

Darin Morgan

The LT1-4 head may flow 277 or even 400 fully ported with valves and everything else BUT, I wonder how many people know that the intake manifold only flows 200cfm. LOL

MatthewMiller

I've been wondering about that. Is that really true? Are the castings different in ways other than the height/size of the ports, such there is more room to port on the LT4 heads? Or asked from the opposite side of the coin, can you not port an LT1 to have identical port shapes and sizes to a well ported set of LT4 heads? I'm not sure one way or the other, because I've heard both answers to that question.

FWIW, way back about 12-13 years ago, the previous owner of my car (MSR, used to be on here) had the OE LT4 heads ported by Greg Good in Houston. With 2.055"/1.625" valves, he got:

• .1 84/56
• .2 157/120
• .3 220/171
• .4 267/199
• .5 297/218
• .6 308/223

I have no idea how much the porting cost, or if Greg is still doing this work. But those are outstanding flow numbers for those heads, and it would be worth searching him out to ask. I also have no idea the cost effectiveness of that vs CNC porting vs aftermarket heads.

The OP was also looking at porting the intake. I know mine is ported, but I have no idea how much it flows. What's the potential for that? I'm curious.

PS - To the OP (STL94LT1), you must be within a few miles of me. Cool!

dizwiz24

where does this come from ????

dizwiz24

agreed. dont screw around with getting existing heads ported.

no one will ever get up to ported aftermarket castings head flow numbers.

there was a head shootout once of afr's comp ported vs. an aftermarket porters best work and the afr's won in hp and a tual dragstrip performance

buy some afr 195 competition ported. also they come in various cc sizes such that you can either increase compression or decrease (ex. for boost) to suit your needs

MatthewMiller

I'm not so sure about that last sentence. Comparing AFR's own numbers for the 195 Competition ported heads to my ported LT4 heads, they are very similar. Theirs flow a bit higher on exhaust at .600, mine flow significantly higher on intake at .300.

Now, what may well be true is that by the time you pay for porting, valves, springs, retainers, etc; you could also pay for a fully assembled set of the AFRs ($2069 at Summit). That is definitely an easier solution. You'd have to compare costs to figure out if it's also cheaper or not. I honestly don't know.