I saw a good deal on a set of Gen 6 vortec heads. What are the issues with this swap? Head gaskets; Valve train?
I'm looking to boost the 8.5:1 compression and have heard they flow well. This will be a torque motor with 5,000 rpm limit.

Go to http://www.sdpc2000.com/ They have the conversion kit for those heads to fit Gen IV Engines..

What makes them a vortec head?I have a pair of a Gen vi motor also?

graemlins/waving.gif
Rick

BBC Vortec heads (http://www.sdpc2000.com/cart.asp?action=prod_detail&catid=281&pid=215)
I couldn't find a conversion kit on the site.

I just love the accuracy of SDPC's data listwed for them!! NOT!!

About 235 cc intake port size!! So are small, large ovals to say the least!! BUT I do like the about 100 cc chambers.

Too bad they don't have 270 or even 290 cc intake ports, (that are true ovals like they are and not "rovals" like the E-brock Sig. Series), with 90 cc chambers, then they would have a winner AND I bet GM couldn't make enough of them!!!!!!!!!!

pdq67

You got to actually call them and they have a special felpro head gaskets and a plug kit so the head wont leak coolant into the lifter vally. Kinda hard to find the kit on there site. I have ordered them before from them for Gen V heads to fit Gen IV blocks.

Originally posted by pdq67:

About 235 cc intake port size!! So are small, large ovals to say the least!! BUT I do like the about 100 cc chambers.
pdq67 Where did you get this port size from?? It was my understanding that they are roughly the same port as the 049 head.

I had to search for it here under the Engine Section so here goes..

"ARTICLE FOUND. Thanks, pdq67! February '98 CHP, in the "Chevy Thunder" section. "Heavy Lifting: Sallee Chevrolet Puts Chevrolet's Vortec Big Block Heads to the Test."

I found my darn mag finally!!!

Spec's on the L-29 Vortec BB head vs a peanut port BB head (PPH) per the article..

L-29 intake ports = 233.2(S) and 239.5cc(L).
PPH intake ports = 192.4(S) and 198.0cc(L).

L-29 exhaust port = 81.2cc.
PPH exhaust port = 101.3cc.

Chamber volumes. L-29 = 100 and PPH = 118.4cc.

Approx. CR's on a regular stock, small domed 502, PPH = 8.74CR. and L-29 = 9.74CR.

For a flat-top piston 502, the L-29 would make 9.3CR.

For a stock 454 flat-top P/U truck motor PPH = 7.9CR. and L-29 = 9.0CR!!

Valves = the same for both heads at 2.065"/1.72".

NOTE: Use Fel-Pro headgasket 1017-1 to use L-29 heads on the early IV BB blocks AND check coolant holes CAREFULLY!!!

A VERY GOOD WAY TO UP YOUR OLD P/U MOTOR's POWER, imho!!!!

Put a set of 2.19"/1.88" or 2.25"/1.90" valves in the L-29's with them reworked accordingly and about a CC 260HE, (or maybe 268HE), hy- cam AND I BET you could pull a bulldozer with a new 502 in your Duelie work truck!! "

pdq67

I have a running 454 Mk IV with Gen VI heads in my boat. Just got it fired, haven't done performance testing yet.

There is NO plug kit OR "special" gasket needed "to prevent coolant leaks into the lifter galley." Gen 6 heads on a Mark IV block is not a coolant leaker. Mk IV heads on a Gen 5/6 block is the problem child.

Use any Mk IV head gasket you like. I went with a pair of steel shim Mr. Gasket units, to get proper quench since my pistons were .020 in the hole.

You need flat-top pistons OR you need to modify the vane in the combustion chamber for clearance.

You'll need special rocker studs (3/8 bottom thread instead of the usual 7/16) and two sets of .300 thick shims to replace the valve rotators.

Big valves in these heads would be a mistake, I think. The 2.07 intake valve is only about 1/8 inch away from the "vane" in the combustion chamber as is. More valve diameter would certainly lead to shrouding and perhaps REDUCED performance. The exhaust seats are inserts. I'm not sure you could grind them out far enough to install large exhaust valves--and why bother? The L-29 head has a truly superior exhaust port. Very small, yet very efficient! The main weakness is on the intake side.

Time will tell-I have a couple of issues with my engine that are unrelated to the head swap. Once they're sorted out, I'll have an idea of the performance potential of these heads. Until then, my expectiation is that these heads will make decent power based on an efficient combustion chamber and good exhaust port.