Do you guys know anything about the L29 Vortec motor. I know they were installed in trucks from 96- 00?. Anyone know if there is any street performance potential in one. It would seem to me that with a replacement roller cam this would be a decent idle - 5500 RPM motor.

I will tell you soon. I have a ZZ502 cam in mine.

The exhaust port is reportedly excellent with minor modification, but the intake port needs help. It does not flow much better than the silly round port truck heads.

Burning is another matter, though. Very good chamber that needs little spark advance to make power. About 30 degrees is all it takes.

The pair I saw looked like the casting work is MUCH better than what was done on the heads in the mid-'70's. Less casting flash, nice detailing.

I have a set of those heads on a Mk IV 454 in my boat.

I'm running a '96 Vintage L29 in my Chevelle. I drive it daily.

I'm not too sure I can give a good description of performance, since I'm running the carb from my old small block. I'm using an Edelbrock RPM AirGap, coupled with a 600CFM 1405 Edelbrock carb. It works, but after 3500RPM she falls flat on her face.

Other specs:
Turbo 350
2.56 rear gear
in a heavy wagon.

She'd probably run MUCH better with a larger carb, but I can't see myself spending 400+ on a carb. I'd rather use that 400 to bring the price of FI down. Not to mention, before I do anything to add more power, I need to get the rear taken care of. Not to mention the transmission issues I'm having.

Chris,

That's a stock Vortec I assume, the cam in it is real small. I have an option of going Vortec on the GenVI motor I have or using the small Rec Port Merlins. Since I first posted this, I have talked to a couple of guys that have done similiar. With a bigger cam, the RPM range is better but falls off at 5000 at best. Still not bad for a street motor, but not really what I am after.

I am probably going to use the Merlin heads with a mild cam and a little more compression. Kind of a Stage I 454HO motor (if they made one).

Thanks for responding.

Chris,that 600 Holley is killing that motor..I ran one on my 454 for about 3 weeks..and that one had the lightest secondary spring,and it had a 50 cc accelerator pump.
It worked decent on a 402 I had it on previously.
I then bought a $179 Holley 3310 from Scoggin-Dickey,and it woke the car right up.
Difference was night and day

Those heads only have like a 135 cc or so intake port even though they are called large ovals....

AND were made to replace the old "peanut port" heads which they did nicely..

Imho, a set of reworked -206's or -215's will do you much better..

pdq67

Originally posted by pdq67:
Those heads only have like a 135 cc or so intake port even though they are called large ovals....

AND were made to replace the old "peanut port" heads which they did nicely..

Imho, a set of reworked -206's or -215's will do you much better..

pdq67 Really??? They look pretty big and matched up perfectly to the RPM Air Gap intake without any porting. I hope I didn't waste a ton of money and time to go slower than the 350 did.

I have one in my 3/4 Ton 4WD, Suburban. Its a tourque monster, even in the 6K+ pound truck.

I'm sure it would perform well in a Driver style Chevelle....especially a Driver Wagon ;) ;) ;)

BTW, if it falls flat after 3500 RPM, I wouldn't know. With the 4:10's and that overdrive I've never gotten that high. On the down side 9mpg.

Originally posted by pdq67:
Those heads only have like a 135 cc or so intake port even though they are called large ovals....

AND were made to replace the old "peanut port" heads which they did nicely..

Imho, a set of reworked -206's or -215's will do you much better..

pdq67 That's nonsense. They have 255cc intake runners. It's the chamber that makes them different, the runners are pretty much like any other large oval port head. graemlins/boring.gif

I had thought the GenVI block that I just bought was from a Vortec, but the heads were no where to be seen. {Note : odd though, my block has the fuel pump boss which I thought was only available aftermarket } :confused: There is a set of Vortec heads on Ebay right now. The intkae ports actually look fairly large and the exhaust ports are the much better D ports. I think the Comb Chamber is the limiting factor in RPM. The heart shape design may shroud the valves in stock form. I would bet a couple of hours with a die grinder relieving the valves would work wonders My feeling is these heads, with a correctly set up combo, would be a stump puller. Idle to 5000 maybe 5200 with a nail you to the seat torque curve. Run em with a 2000 - 2400 stall conv, 210 - 220 @ .050 cam (GenVI roller) and some 3.31 gears with a T400.

Crazy how it all comes about. I am ready to build my 454 and discussing piston options to use the Open Chamber heads I have. But I am really curious to find out what a reworked Vortec would run like. Who is going to be make the sacrifice?

Man, if I could only find a set of reasonable ($$) brackets ... I'd have mine in there now!!

Like I said in my other post, I'm thinking this thing has got to be good for at least 5k rpm. They do that in stock pickups.

HP ... I'm trying to find a thinner head gasket, and 454HO take-out cam, and thinking 375HP is a reasonable goal.

Your block sounds odd though ... GenVI production blocks definitely do not have a fuel pump or Z-bar boss. Might want to run some www.mortec.com (http://www.mortec.com) number and see exactly what you have?

Definitely interested in your post though ... and what other's can offer for mild-performance?

Thanks, Neal

Actually Neal, the replacement production blocks that Chevy sells (same as the 454HO block) have the fuel boss. I am inclined to think, the one I have was intended to be used for a rebuild.

The only flow data I had seen for Vortec Heads showed very good low lift flow, but the flow rate flattened out at about .400 valve opening. Short of extensive porting, I think duration and rate of lift will be more important with the Vortec head as opposed to sheer lift. Also, with the oval ports, the exhaust may not need as much added duration as 454HO with the rec ports and low comp. Inclined more to match the ZZ502 cam with the Vortec head.

Originally posted by TJC:
</font><blockquote>quote:</font><hr />Originally posted by pdq67:
Those heads only have like a 135 cc or so intake port even though they are called large ovals....

AND were made to replace the old "peanut port" heads which they did nicely..

Imho, a set of reworked -206's or -215's will do you much better..

pdq67 That's nonsense. They have 255cc intake runners. It's the chamber that makes them different, the runners are pretty much like any other large oval port head. graemlins/boring.gif </font>[/QUOTE]I think PDQ meant to say 235cc which is correct.
They do have a normal large oval opening but have the "ski ramp" swirl inducer under the valve, in the critical bowl area.
I think they would work excellent on a 5000 rpm 454 in absolutely stock form.

They would need help above this but so do the older ovals...

On a stock L29 I would do a cam swap first, then be sure all the other stuff was matched, headers, intake, carb..

It would be a killer mild street motor capable of mid 12's without touching the heads with the right parts.

Anyone know where to pick up a take out ZZ502 Cam?

Originally posted by Chambers:
Anyone know where to pick up a take out ZZ502 Cam? call Competition Products

Thx, Jake, you are right!! I saw I had screwed up earlier and just left it b/c I'm not the best ta try ta edit my post is all..

pdq67

I know this thread is OLD, but for others stumbling on it:

The 96-2000 vortec heads are 99cc chambers, giving 9:1 compression.

7 years ago. Been through a lot since then. Never did use the Vortec heads or the Merlin rec ports.