Engine Guru's and those that have done vortec heads on a TBI...

[heavy4x4]

Engine Guru\'s and those that have done vortec heads on a TBI...

2 questions for you.

1) I know the vortec heads require the special intake manifold (for $300 /forums/images/graemlins/frown.gif) because there are 4 bolts per side instead of 6. I think I also read on here that the bolts furthest to the rear are at a different angle. If this is true, will I still be able to bolt the throttle bracket down using these bolts? The bolts are at the same spacing too, right? Also, does the manifold have everthing else I'll need for bolting stuff on? And, do I still mount the egr valve atop the intake even with the exhaust tube crossover?

2) My '90 TBI 350 should be externally balanced. So, how do I balance this engine when I do a rebuild? In 85-earlier 350's you just balance each part of the rotating crank assembly individually, but with an externally balanced I won't have to do that, right? Well then how will I know what weights to use on the flexplate? Do I have to take it to a shop and have them figure that out? Sorry for all the questions...but I'm really clueless on this one.

Thanks for your help.

 

[fortcollinsram]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

I don't have a Vortec 350 so no clue on the first Q...

But your 350 should be INTERNALLY balanced. TThe machine shop that does your block and head work should be able to hook you up with a good internaly balance job...My shop charged me like $125 for the internal balance of my 454...The basically balance all the componentes (rod, pistons) and get those weights to match and then the weigh the each cylinders reciprocting mass (piston, rings, pin, rods, bearings) and put a boba weight of the weight on the crank and spin it to balance it dynamically (ie spin it and then drill holes in the crank to remove weight or add mallory metal to add weight...My shop neutral balanced my Harmonic Balancer and flywheel so if I ever get a new one, I just take it to them and they neutral balance the new one....

BTW, to keep the price of a balance job down, try to use LIGHTER components than stock so Mallory Metla isn't needed...it can easily double the price of a balance job...

Chris

Chris

 

[dyeager535]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

1) Vortec intake bolt to head spacing is *different* than previous "patterns". Just found that out last night...my '88 TPI coil bracket won't work /forums/images/graemlins/frown.gif The angle probably wouldn't make too much difference (just bend it) but since the bolts are further apart, I'm betting the bracket won't work at all...the bolts for the vortecs are far enough apart that the bracket isn't wide enough to re-drill.

The EGR is probably run like the TPI vortec intake..valve is where its "supposed to be" but the feed is from an exhaust pipe. As long as the intake is setup for it! Manifold SHOULD be an exact duplicate of a stock TBI intake except for the hole spacing/intake port size. I'd be kinda ticked if they didn't replicate everything else so it was a "bolt on" deal.

2) Engine balancing, take it to a shop. You can't balance it like they do, and for $125 (or so) you are getting your moneys worth, especially for all the components they plug into the equation. Hypereutectic pistons keep the weight down, and are cheap.

 

[heavy4x4]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

Well, found a good pic...those bolts are DEFINITELY angled differently, but they look about the same spacing, do they not? /forums/images/graemlins/confused.gif

HMMMMMM...wonder if this is what I need to get. Any opinions?

I'm really trying to keep this as bolt on as I can get. I hate having to modify stuff that should be equipped with the right stuff for the application...especially when it costs $300.

Who out there has done the vortec head on a TBI swap? Speak up please. /forums/images/graemlins/grin.gif

 

[indiana88]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

I've been wondering about this myself. The only way I have heard of being able to use the stock TBI on Vortec heads is with the Edelbrock etec intake. Is there a different way? Or is this the "special" manifold you were taling about?

 

[heavy4x4]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

That picture I posted above is of the manifold necessary for vortec heads while using a TBI.

So, nobody on here has done this /forums/images/graemlins/shocked.gif Come on, speak up /forums/images/graemlins/grin.gif

 

[BigBurban350]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

Where did you find that TBI vortec intake. I myself am planning to do a vortec swap on my TBI and i dont want to goto a carb. Summit sells a high flowing TBI unit so i can enjoy the extra torque. /forums/images/graemlins/usaflag.gif /forums/images/graemlins/burb.gif /forums/images/graemlins/usaflag.gif

 

[heavy4x4]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

Sallee Chevrolet...It's a dealer in Oregon, but I figure the prices and products should still be the same at your local GM dealer. Also the only good site I've found so far that has GM parts and prices. /forums/images/graemlins/thumb.gif

 

[dyeager535]

Re: Engine Guru\'s and those that have done vortec heads on a TBI...

I've got a set of Vortec heads bolted to the 355 block in my garage, and the '86+ Camaro TPI bracketry that will be going on it, sitting there as well. (along with the intake I can't use)

The Vortec hole spacing is 2.67" (or so) while the '86+ intake pattern spacing is approx. 2.3" (yes, I just used my dial calipers to check), so no, it won't work. The bolt holes are less than 1/8" from the edge of *my* bracket, so there simply isn't enough metal for me to just re-drill.

Looks like you found the "right" part, although that bolt/bolt arrangement looks to universal for my liking. I'll probably just bend a piece of steel for my app, since I'm not holding the throttle cable with it.

Check the etec intakes. They should be cast with an exhaust crossover that you can't use, but not sure if that would melt the gasket and cause problems or not. I'm betting so since the vortec intake gaskets are plastic there. Guess you could ask Edelbrock. Edelbrock isn't selling a copy of that GMPP manifold?

I know they aren't selling the intake for the Vortec/TPI swap, but I know they are making the only one there is, for the sole GM dealer selling them.

Unfortunately, this is one of the scenarios in which the Vortec heads "aren't all that". Some Etec or similar heads would be a better option I bet...cheaper intake, no EGR problems, better springs, etc.