123jon321

I just got done reading a great many post about the possibility of the lt4 intake working with the vortec heads. Did anyone ever actually attempt this? Many people said that the ports were the same and that it would work with only the drilling and tapping of the heads, but it seemed noone had tried it. The posts go as far back as early 2002, should I assume that if it hasn't been done by now that it doesn't work?

John Millican

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The Vortec/Fastburns heads are in a league of their own. I do not convert LTx intakes for them at all. The Vortec head itself would need modified too if you are determined to do this swap.

jlbolin

heres another ? is the intake bolt pattern the only problem cause of the vortecs not having the traditional pattern.if so then all you need is the heads drilled and tapped right?just trying to rule out possiblities. getting ready to do this swap between vortecs and changing a tpi intake to an lt4.is there any thing im missing that i dont know from experience.

John Millican

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You just might drill into water if you try that. I don't know for sure.

1bad91Z

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The fast-burn heads are drilled for both style intakes (from the factory). You can drill and tap vortec heads just the same!

If you remember, there was someone here that used vortec heads with a stock lower GM TPI manifold. He had to drill and tap his heads and add metal to the intake, plane it out smooth, and it worked.

You wouldn't even have to go through all that to get a LT-4 intake to work with vortec/fast-burn heads. Fast-burns are allready prepped out of the box, but if you use vortecs, have a machine shop drill and tap the vortecs for old school bolt pattern.

The LT-4 intake allready has the same port shape as the vortec/fast-burn/e-tec/LT-4 heads. ANything is possible and using a LT-4 intake with vortec heads is not only possible, but it would be just as easy to convert as an LT-1 intake is to convert to regular sbc heads. You just need to drill and tap the vortecs and then just mod the LT-4 intake like you would normally mod an LT-1 intake.

Just my $.02

123jon321

I'm planning on doing this real soon with my vortecs. I'm goint to order the intake in the next week and see how it lines up. Aren't the fastburns structurally, on the outside, the same exact thing as the vortecs(besides minor port size differences of course)? The only thing I'm weary about is the fact that this has been talked about for over two years and yet noone one has done it. With the mass of people with vortec heads why aren't they all jumping on this? The cost is hardly more than the SDPC intake:

Intake: $230
Remote thermostat housing: $65
Custom fuel lines: $85
Fuel rails: between $50-$150

That's between $430-$530 for essentially the most breathing that almost anybody on here with vortecs is going to need. Can somnone tell me what I'm missing?

1bad91Z

iTrader: (1)

It's a pain to do the distrib hole and spacer on the backside of the intake and John Millican said he didnt want to do the conversion.

Most people that I know get their LT-1 converted intakes from John Millican, so the above is probably why no-one has jumped on the idea yet!

It will work John, you could add to your cash flow if you took this on.

Customers can buy the LT-4 intake with fuel rails from Summit racing pretty reasonably priced and ship it to you for the conversion. Also, leave the head drilling and tapping upto the customer. No implied or expected warranty or gaurentee it would work..... I'd still be willing to bet you would have people lined up to do this!

Roostmeyer

iTrader: (3)

After just completing the swap (now I've got ECM and tuning problems to work through) I agree with you 1bad91Z on most of that except for one thing. Why drill the heads for a standard intake pattern and still have to do all the extra work to the intake? Just get them drilled for the ?72? degree intake holes on the lt4 intake. You won't have to worry about spot facing around the bolts (thats a great idea by the way john on how to do it on your site, I just wish I had seen it before my intake was on my car)

Possible problems that may arise are drilling the heads at that angle won't be east as the drill won't want to go in straight(maybe spot face around the holes first?), and an lt4 intake gasket probably won't have open coolant ports, so you'd have to modify any gasket to fit.

The distributor hole is not hard to drill at all. I used a 1 3/8" metal holesaw bit, its not pretty but it works. John will sell the spacer seperately, worth it IMO. Don't worry about the distributor hole being right on, you can dremel the hole out a little bigger without any problems if your a little off. The distributor is smaller at the surface of the intake than it will be where it goes through the spacer anyway. I drilled mine from the back of the intake and waited until I fitted the intake on the car before I installed the spacer on the intake. Also the distributors location is held by the block, not by the intake. However the distributors height is determined by the intake.

Cliff notes, the hole in the intake doesn't have to be perfect just make sure the distributor spacer is.

John Millican

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I won't do the full LT4/Vortec conversion but i do a "distributor only" conversion that people might want to conside if they want to attampt this. It's $100 labor if you send me the core LT1/4.

Summit sells only the bare LT4 intake, not the fuel rails. If I am wrong please let me know.

1bad91Z

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I called Summit to find out. They said they dont sell the rails. However, you can get brand new rails from www.gmpartsdirect.com

or find them used somewhere.

bnoon

Now I have to rethink my whole setup. I read through the whole LT4/Vortec possability before deciding on doing the 416 heads and LT1 conversion because I didn't want to be the pioneer on something that could turn out to not work. Now that people are saying that the ports would indeed line up, that only leaves basic intake bolt and water jacket issues that are already being covered in the basic LT1 conversions anyway... Hummmmmmmm

Just FYI, I got my LT1 rails on ebay for $30 shipped and they do swap over to the LT4 from what the Summit ad states IIRC. EDIT: Yup, just double checked. The LT4 works with the stock LT1 hardware from '94+ intakes.

1bad91Z

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The first one to pioneer this LT-4 / vortec head combo is all it should take hopefully for John to realize the potential of the extra $$ that would be in doing this.

John, I know you could make it work!!

BLOWN85/TA

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I emailed with a guy on this list about using the LT4 intake a while back. He had it installed for about 6 or 8 months then. That was right after SDPC released the Vortec TPI intake. I dont remember his ID or email but he did it. I remember he had a few other problems fitting it, but got it done. Do some hardcore searching and see if you can find his posts. I went with the SDPC intake, but the LT4 got my attention.

1bad91Z

iTrader: (1)

The LT-4 has had my attention ever since I had to wait 6 FRIGGIN' months to get my SDPC vortec intake (they were on back order at the time about a year and 1/2 ago).

BLOWN85/TA

iTrader: (2)

Tell me about it! I bought a new one from a guy that changed his mind. I got lucky to get one and at a better price. I had it ported by a renowned porter in my area, he shaved a HUGE amount of aluminum from that thing. Like a coke can amount.