Hey has anyone ever tried this combo before ? I have the opportunity to buy a set of the aformentioned heads for $600 from my next door neighbor and i was wonderin if it was compatible .

 

DON'T DO IT!!!! The castings are thin, prone to cracking. They don't flow anywhere as good as stock Vortec's to begin with, and they more than likely WON'T have accessory bolt holes in the front of the head ( for brackets ) and they SURE aren't worth $600 from a performance standpoint.


Pick up some Vortec's ( $550 pair new ) or a set of iron Pro Lightning heads for $700 or so....



HTH

 

I forgot about the accessory bolt holes ! Your right , they wouldn't have them ,at least not for accessories for an '86 . Damnnnnnnnn good thing i asked or i would have wasted my money real fast ! Thanks for the info !!!

 

They are not thin, not prone to cracking, and some do have accessory bolt holes. The ones I have been running on my 400 and that I have in my car right now are both that kind; 186 casting, with bolt holes.

But $600 is really steep. They would literally have to be fully worked up - and I mean screw-in studs & guide plates, professionally ported, undercut valves, etc. etc. etc. to be worth that kind of money.

 

ooops i forgot to mention that my neighbor is a pro NHRA/IHRA drag racer and yes the heads are fully ported /polished and rebuilt . Should i ask him for less money ? should i look for certain casting numbers ? I am going very slowly with my parts purchases because if i buy something wrong , I wont have the money to make it right . geeezzzz , I knew there was a reason to stay single !!!! LMAO !

Thanks again guys !

 

i forgot to add that they come ready to bolt on ie : screw in studs guide plates ,roller rockers.... but do you guys think they would actually work on a TPI setup since they were worked for a drag car ? i have a totally stock TPI setup right now but that will be changin ,I just dont wanna buy the wrong heads for a totally street driven car . Especially since i can buy a used set of vortecs and a vortec tpi manifold and come close to the same price range.
choices , choices , choices ! Im gonna go check them out tonight against my stock heads to see if the accessory bolt holes are the same , if they arent , then its case closed .

 

You may be able to buy the used Vortecs and the $$$ Vortec base for the same money, but you'll have alot more than $600 by the time you can actually run them and get any benefit from them. They come with valve springs that will barely control a 929 cam up to 4000 RPM when new, pull-out studs, 3 lb valves, etc. etc. .... totally anti-performance. The only thing they have going for them in stock form is flow: every single other detail you'd want for a performance application is lacking. So what you're really looking at is a set of used heads for whatever you have to pay, plus probably $400 parts and labor just to make them survive longer than 3 magazine article dyno pulls, plus the base. Whereas, if the double-humps have the bolt holes, they're a bolt-in. The Vortecs will make somewhat more power (better flow) after some massaging though.

If you keep a stock TPI, it will also need its base extensively ported to get much benefit from the heads. Otherwise you end up installing an extra plenum at the end of each runner, in the form of an intake port that looks like a "chamber" instead of a "runner" to the rest of the system.

 

You're right.......I automatically thought of 462 and 461(x) castings....as that was one of the most sought after heads on roundy-round motors that had to stay within the rules. And these of course don't have the accessory bolt holes.

And you're right again... I meant to post that more than likely a set of these heads has been around the block a few times, which normally means getting decked / milled....

So this time I'll get a bit more accurate....good catch.

The double-hump markings encompass a number of SBC heads, including ( I'm sure I'll miss a couple )

- '186' As he mentioned.....and again I think these were limited to 69-70....not the easiest to find...at least around here...


- '492' these were LT-1( note the '-' , not LT1 ) production castings...pretty sure just in '70 maybe early '71. A few Nova's had 'em, but mainly Vette and Z28 production pieces...these only came with big valves ( 2.02 intake , 1.6 exh )

I also believe GM marketed these by themselves from the dealership. I remember seeing a couple of sets with angle plugs.....

- '291' - 67-68 year 302-350 heads....both small valve and big. No accessory holes


- '292' I don't remember what these came on from the factory, but GM sold them by themselves as well. Crane Cams also sold a head with this casting.....Most people call 'em Turbo Heads...


- '041' just remember 'em having the double hump mark...not much else


As for the price.....I still agree it's kinda high. I'd almost want to see some flow numbers....guess I'm picky...or at least find out who ported the heads, and what they were used on..

As for the Vortec's...YES they aren't optimum for MAXIMUM performance out of the box, they are stout enough to handle a healthy cam up to about .490 lift or so, and being that most go with a non roller cam, this is alot of cam for a street driven 350......depending on the duration as well.

I've seen these stock Vortec's dyno'd on a mild Q-Jet equipped truck that wasn't even tuned as well as it could have been, and with NO other changes, the Vortec's and the Performer Vortec intake were worth almost 60HP on a 350 w/ 9:5 to 1 over a set of 882's with big valves and a regular Performer intake.

A cam change to the XE268 was worth another 35HP ....

In fact, a friend of mine runs 13's in a BOAT of a '70 or '71 Monte Carlo with the stock Vortec's and a XE268 w/ Performer RPM intake.....


It's all in where you plan the car to end up at....and how fast ( $$$ ) you want to get there.

Are the heads better than a stock L98 or LB9 head...yup, depending on the casting, I'm sure they would be. But for $600 you could buy a complete cam kit, timing set, valve job, and the tools to port the TPI heads to flow just as well , by doing it yourself. Hell, if I can do it anybody can......just remember these key words.....SAFETY GLASSES and a shop vac with an extension......


HTH and sorry for any mis-info I put out.....

Later
Chris
85 IROC
A few mods...
New Taylor wires and looms tomorrow...and it's going to be 40 degrees...lovely.