[454C10]

4.11 gear with a 4 spd already has "low speed torque" due to the engine revving so high. That combo needs an engine that makes power in the upper rpms (unless it is going into a tow truck).

what he really needs in a set of headers to make that mid rpm torque!!!

a 292H makes a nice "weekend" street cam. I have used that cam as just that and loved it. He isn't building a daily driver.

I have near that 350 setup with a 3.90 gear with a 5 spd in a 2800 pound car with 200cc darts. 1st gear is all torque and traction is very bad on street tires. Thankfully the engine pulls to 7200 rpm which gives 1st gear some pull at the end of the rpms when the tires stop spinning in the 6000 rpm range. With a smaller cam, 1st gear isn't usable, well maybe for a parking lot. Even with the 292H, I take off in 2nd gear most times.

the 292H is back to making torque at 3000 rpms which would be around 20mph in first gear (4.11 gear, 2.75 first gear, 26 inch tire).

[ap72]

I'm sure that works fine for you, but its not what the poster asked for. I see this a lot in my line of work. Engineers trying to design to their limits when a client just wants a simple and effective solution.

[my87Z]

yes but i dont think the OP is looking for that aggressive of cam for what kind of drivig he plans on doing, and that is a larger duration cam for a 350 so it will be even that much more aggressive in 327

not saying that it's a bad cam a buddy of mine runs that in his street/strip C-10, i just think that's a bit much for what he is looking for

[454C10]

I gave the guy options.

he can keep more compression with a bigger cam or drop compression with a smaller cam. Maybe the guy doesn't really want to change the pistons.???

also made a recommendation with a 350 build that he would love. Because, if he puts small cam in a light car with a 4.11 gear and manual trans, then it will drive like a tow truck. When someone wants to jump off a bridge I try to convince them otherwise.

a 350 with a big cam and 4.11 gears with a manual is not my invention. It works for everyone.

[automotive breath]

Originally Posted by Rickracer

My information comes from my machinist, who's done all my work for over 25 years, does a TON of local racer's porting work, even has some national record holders, and owns his own Superflow 600, but I'm always interested in more knowledge and/or different perspectives...

Always listen to your machinist over some nobody on the internet. If you
don't, find another machinist. He is likely fixing some of the obstructions
in the vortec heads with his valve job. Besides its not cost effective to pay
much for porting vortec heads, if someone is going to get into them that
deep money wise, it’s best to start with a better casting IMO. Now if you
do the work your self, it’s a different situation. I’ll post some pictures of a
set I’m porting now.

You and I are on the same page with the RPMs. These small journal engines
handle RPM very well and anyone planning to spin one up should invest in
a good set of forged pistons. If you go back and study the combination I
posted, it’s really very mild with a power peak well below 7000 RPM, should
make over 400 HP.

[automotive breath]

Originally Posted by 454C10

... Maybe the guy doesn't really want to change the pistons.??.

You are so right, why change the pistons if they are in good condition?

[Hippie]

Originally Posted by automotive breath

If you go back and study the combination I posted, it’s really very mild with a power peak well below 7000 RPM, should make over 400 HP.

According to DD2000 with AFR 195 Eliminator heads it would make "about" 441 FWHP @ 6500 and 412 FWTQ at 4500 and 5000 RPM so Peak TQ would be slightly higher somewhere about 4750. Yeah, it would be a lot of fun, definitely would leave no doubt to even non-car people that it was NOT stock.

My question is, where did the OP go? Still an interesting thread though even if he did bail on us.

[Rickracer]

Originally Posted by automotive breath

Always listen to your machinist over some nobody on the internet..... He is likely fixing some of the obstructions in the vortec heads with his valve job...... I’ll post some pictures of a set I’m porting now.

He says most of his flow 238~242 after the valve job, also says he can get 10~15 more but it's not worth the trouble. So I think we're still on the same page. Apparently, you and I think nothing about taking a die grinder to a perfectly good set of heads, , but the average Joe can really mess them up badly without some teaching and/or experience, that was the reason I considered it bad advice,

[ap72]

maybe I have too much faith in the average joe...



I consider myself average, but who knows.

[ap72]

here are some old vortec pics I have, I don't know if they're from the same set or different ones... I really need to label pictures better. It shows what a "average joe" can do with about a $100 investment in tools.

[Rickracer]

Not to pick on you, but while they look good, I would bet money those don't flow as much at .150 to .400 lift as a bone stock set out of the box, which is where the stock Vortecs with a GOOD valve job really shine. Got any flow numbers on them???

[ap72]

Originally Posted by Rickracer

Not to pick on you, but while they look good, I would bet money those don't flow as much at .150 to .400 lift as a bone stock set out of the box, which is where the stock Vortecs with a GOOD valve job really shine. Got any flow numbers on them???

unfortunately, no. I have a few sets of heads I was going to take to my buddy's place all at once (he's two hours away), but with an upcoming wedding and house buying time is well... non-existant.

I'm curious though, what would you change? These were all taken before the valve job. The SSR is a hair flat at the top but I did my best to give it a good curve, they cc out right at 180. I would take some more of the current stuff i have but my camera was stolen when my truck was broken into.

If you could give me some details I'm all ears. I've talked to a few head porters for tips and tricks but I'm just the average joe. I design landfills for a living.

[Hippie]

Originally Posted by 454C10

4.11 gear with a 4 spd already has "low speed torque" due to the engine revving so high. That combo needs an engine that makes power in the upper rpms (unless it is going into a tow truck).

With a smaller cam, 1st gear isn't usable, well maybe for a parking lot. Even with the 292H, I take off in 2nd gear most times.

the 292H is back to making torque at 3000 rpms which would be around 20mph in first gear (4.11 gear, 2.75 first gear, 26 inch tire).

He has an M-21 close ratio Muncie with 2.20 first gear. Assuming a 26 inch tire he would be turning 6400 RPM @ 55 MPH in 1st, that better be one long parking lot!

[Rickracer]

Originally Posted by ap72

...I'm curious though, what would you change? ...If you could give me some details I'm all ears.....

I used to do a lot of porting, my 492s got the full treatment, the oval ports on my 427 flowed more than a set of stock square ports with MUCH better velocity and low end, did quite a few circle track heads for another shop here in town, but that was years ago, and they were a lot different animals than the Vortecs. Dennis, my machinist, would be the guy to ask, there are companies that make CNC plots from his port work for some of the import stuff. I just know he's told me several times that almost anything done to the port walls and bowls hurts flow, not help it. Chevy really did their homework on the Vortecs.

[ap72]

i didn`t change the bowl much at all though i did get into the runners some to straighten them out. i really need to get this stuff tested. got to get it by th misses to be though.