I was reading another post/thread and I noticed someone put an LT4 intake (which has the same bolt pattern as the LT1) with what I thought were 96-98 Vortec Heads. Is this possible, does anyone know if the LT1 bolts up to Vortec heads?

John

 

Has been rumored, but no actual proof as far as I can tell..

As far as fit, if any of them were going to fit the vortec heads it would be the LT-4 or the L99 intake.

The vortec has a taller head port(intake) than conventional small block heads.

The above listed have taller intake ports as well.

Curious, I would do this if I knew it fit, maybe I need to grab a L99 intake next time im at the yard.

later
Jeremy

 

I'd swear that the guy doing the LT1 intake conversions said that LT4 fit. A simple gasket comparison might tell.
The Ramjet intake fits.

 

Yes,

maybe the great Millican will bless us with his presence j/k lol


He would more than likley have proof. I know he was looking for one to test at one point, I dont know what happened however.

later
Jeremy

 

I guess I wonder how well the LT4 Intake, with the Vortech heads would work on my 305, and then make a custom chip.

John

 

The LT1 bolt holes do NOT match up to Vortec head bolt holes.

People have done their own LT4/Vortec head combo but I do not attempt it. I am already busy enough with standard LT1 intake conversions.

 

There is no such thing as vortech heads!!!!!!!!!

 

Enlighten us oh wise one.

John

 

There is no such thing as Vortech heads. Vortech makes superchargers.

However, GM makes a Vortec engine. Many infact.

-- Joe

 

Ok, my mistake, Vortec NOT Vortech...

So shoot me.... Anyway, thanks for the help.

John

 

So, anyone who had done an LT4 or L99 intake swap using vortec heads?

Anyone?

later
Jeremy

 

i know there is at least 1 guy.. i saw a picture on here not too long ago where a guy took the LT1 intake, added more material to the manifold for bolts, not sure if it was an L99 im pretty sure it was the LT1..

 

Thats kind of what I was thinking the L99(maybe) and I'm pretty sure the LT4 intake clears the ports on vortec heads.

HAve to play around with one and see what has to be done.

Basically he added aluminum where the end bolts need to be for the vortec heads and then milled it flat and drilled the holes?

Thats kind of the approach i was thinking of possibly trying.

Now I need some vortec heads and an lt4 intake to just try and match up....

later
Jeremy

 

Is there anyone here who can chime in and tell us if they have successfully accomplished this?

later
JEremy

 

it can be done, the lt4 ports would be ideal as they have a taller port then stock lt1s... either one can be made to work basically but if your going to go for it atleast use the port matching lt4 mani... only hold up in the bolt hoe angles...

 

The vortec heads fwon't fit unless they are specifically made for the lt1. You can't order the ones from summit p/n#12558060 and have them work. The coolant flow is different. If you look at part description is specifically says this.

 

G.M. makes vortec heads that are drilled with the 6 bolts per head intake mounting holes. I cannot verify if they will bolt up to an lt1/lt4 intake but G.M. also makes a gasket set # 12497760 that fits these heads and has both bolt patterns for mounting, and that would be the cheapest way to determine if the bolt pattern would line up or not.

#25534351 small intake port 177cc int/65cc exh
#25534421 SMALL PORT COMPLETE WITH VALVES. Intake are hollow, exh are sodium filled. Comes with LT4 valve springs. Has both valve cover mounting holes (OLD/NEW). Has screw in rocker studs. Large valve spring pocket machining. will accept up to a .530" LIFT CAM without modification. G.M. STATES THAT YOU MUST USE A RAISED RUNNER DESIGN INTAKE MANIFOLD. With that in mind the LT4 intake would be better because from what I understand the LT4 intake has a raised runner.

#25534371 large intake port 206cc int/77cc exh
# 25534431 LARGE PORT SAME SPECS AS SMALL PORT OTHERWISE.
both with 2.00/1.55 65cc chambers.

I COULD ORDER THESE FOR - SMALL PORT COMPLETE $476.67 EACH, PLUS FREIGHT. LARGE PORT $507.14 EACH, PLUS FREIGHT. STANDARD VORTEC COMPLETE $301.00 EACH, PLUS FREIGHT. TIM AT 1-800-666-1171 EXT #1.

 

now thats the info i needed... thanks espirocz


any chance you know the cost of the heads?

 

That is the bare 200cc head p/n.
I get $336 for 1 delivered to CA at GMpartsdirect.
SDPC listed $335 or so plus delivery I'd imagine.
The complete head p/n was listed in CHP or one of the other mags. Think they said $589. But no pair each or anything useful.

 

I put the lt4 intake on my vortec motor. It should be running by Memorial Day weekend. It's taking so long because I bought an 86 corvette with no motor or wiring under the hood. I'm on a tight budget (wife doesn't understand the need for speed) and scrounging up parts takes time.

The lt4 ports and vortec ports match up, just no way to bolt the intake on. The vortec heads are too thin where the bolts need to go so to drill and tap for the lt4 intake didn't look good to me. I had more metal welded onto the corners of the intake and used the factory vortec gaskets. They have thick o-ring type material around all openings and are reusable. Only problem I've run into is Corvette specific parts are expensive!

 

305 Vortec heads vs 350 Vortec heads

I have friend who had a 305 Vortec in his 97 1/2 ton puckup, and it was faster than his dads 95 350 1/2 ton. I know they changed both the 305 & 350 in 96 or 97, but do they use the same heads, or does the 305 use different valves like the other year V8s when compairing 305's and 350's

My question is this, since I have a .040 over 305 (312), would I be better off going with the Vortec 305 heads or the Vortec 350 heads?

Or should I scrap the p.o.s. 305 and put in a 350 (don't answer that one).

John

 

throw away the 305 and go with the 350 :-) I answered it for you :-P

Also the 305 vortec heads and 350 heads are indeed different and you want the 906(doubler check this) casting 350 head only.


Back to the topic at hand. We know the LT4 ports line up to the vortec heads that have a higher than conventional intake port(standard sbc heads).

Has anyone test fit an L99 intake(baby LT) to a vortec head port?

The LT4 ports are the tallest, would the L99 work, they give these things away like candy.

How much material buildup have u had to do at the corners of the intake to make a suitable mounting pad for the vertical bolts?

Biggest concern I would see would be the strength in the rewelded ends of the intake and holding down with only the 8 bolts on the ends only(vortec style)

Got some pics for us Larry.

K-Mart cheap mods that work are where the $$$ is :-)

If I can do it dependably, I just mya be swapping this onto my 383 cause I'm not yanking heads again lol. Whats init already stays there.

later
Jeremy

 

You want the 062 casting, not the 906. If you get one of those 2 heads however, they will not work on the LT1. If you buy them brand new you get the 062 casting.

 

I dont see any reason the LT1 style intake wont work on the vortec heads...

Drill the distributor hole per standard small blocks.

Weld the orignal bolts holes and make pads at the ends only.

Then cut down to same heighth at all 4 holes and the redrill at a straight shot to the orignal vortec bolt holes.

I'm going to measure the bolt hole spacing but it looks incredibly close if not exact, just at an angle.

I will have to see if the L99 intake or LT4 intake will clear the ports as the Lt1 will not.

later
Jeremy

 

Here is why gmperformance parts

Scroll down until you find part #12558060. about halfway down.That is the part number for vortecs with either casting number 062 or 906.

If you don't want to look for it here is what gm says;

12558060 Cast Iron Vortec Cylinder Head Assembly
America's favorite high performance cast iron small-block cylinder head offers big power and bigger value. The Vortec cylinder head's fast burn combustion chamber and high velocity ports combine to produce big horsepower out of the box. The Vortec head can be midly ported for additional performance and can be milled up to .040" for increased compression ratio. The Vortec head uses 1.94" intake valves and 1.50" exhaust valves to compliment the high velocity port design. The Vortec head out-flows the bow-tie head out of the box and is a 20 to 40 horsepower bolt on increase over earlier cast iron small-block heads. The Vortec requires a Vortec style intake manifold due to its improved manifold mounting flange and gasket design and raised intake ports. It is not recommended that the heads be modified to accept early design intake manifolds. Manifolds available are P/N12366573, 12496820, 1249621, 12496822. Vortec heads fit all small-block engines produced 1955 to present, excluding LT1/LT4 reverse coolant flow engines and current LS1 style engines. Heads come completely assembled with valves, springs, retainers, and 3/8" rocker studs. Requires the use of self aligning rocker arms.

Technical Notes: The maximum camshaft lift is .475". The valves seats in these heads can be machined to 2.02" intake and 1.60" exhaust. The rocker arm studs can be pinned or drilled and tapped 3/8". (Casting P/N 10239906 or 12558062.)

 

vrtc350,

U need to get out of the catalogs and into the real world here.

How do u think they run LT1 intakes on conventional small blocks?

Check out Lt1intakes.com(millicans site) and you will see what I mean.

Catalogs tell me things I cant do all the time. Does that catalog also say you cant run 98+ Ls1 brakes on a thirdgen?

I'm not bashing you, just there is alot more going on here than what they say I can/cannot do, and you could say I'm pretty handy at making things work :-)

As far as I can tell, outside of the bolt angle issue and port heighth I am thinking I can make this work :-)

later
Jeremy

 

https://www.thirdgen.org/techbb2/sho...hreadid=257715

found that need tidbit while i was searching some more:-)

later
Jeremy

 

My bad, I was going backwards. I was thinking vortecs on LT1 block. It is obviouse that you can put the intake on. I found an article also by popular hot rodding

Sure things aren't alway set in stone. I have seen a Jaguar with a chevy 454 stuck in it. Also the LS1 brake conversions and other swaps It is a fact that sometimes things just will not work. However right now is not the case. I guess everyone at GM are morons, Summit and Jegs also for that matter.

Really? Sounded like it to me. Look I don't want to get into a shoving match over this because it is pointless. But you can't discredit everything that is written about a part and I'm not about to because you say you can make it work. Once again, I was going backwards and was wrong. But I wouldn't stick a set of vortecs on a LT1 block. Which is what the gm site says. Not anything about the intake! Well nevermind they are morons.

 

This sounds just like my current project. I have a 84 vette that I am almost done with. I have the fastburn GMPP heads and a port injection mercrusier intake. Does the LT4 intake clear the hood without problems?

I was extremely close to buying an LT4 intake and modding it to work, If yours works out I might just do that over the winter.

thanks

-Mike

 

What GM is trying to tell you is that the Vortec heads shouldn't be drilled for any of the earlier design intake manifolds. the reasoning is that to drill the Vortec head for a standard intake pattern you have very little room thickness wise.
With that being the case people modify the intake to the Vortec intake bolt pattern.
Hot rodders won't be stopped by trival stuff like "not fitting". That's what makes it so interesting, especially now with the internet you can pick otehr peoples brains and get more ideas.

 

True. Like I said, I was thinking the wrong way. If it wasn't for the internet, I would still be thinking the wrong way. Sometime things aren't clear as mud.

 

Mr. Millican,

Have u done an lt4/l99(still wiaitng to find out if they work?)

How tall did u make the end pads from welding up aluminum and then maching them down for flats?(if u have done one or whoever else has)

Thats what I'm trying to work out, going to see if I can locate and LT4 intake for measurements, I believe the end heigths are the same as an LT1 intake and I have access to one of those.

later
Jeremy

 

The vortec/lt4 is running! Should take about two weeks to wipe the grin of my face.

 

Larry,
as soon as you stop smiling, please fill us in on what you did to accomplish this task that seems so daunting.

John

 

Larry,

u got some up close and personal pics of your intake or measurements on how much u built up the end pads for the bolt holes?

later
Jeremy

 

I cut the corners off a vortec truck manifold and welded them on. Anyone interested in photos PM an e-mail address so I can attach bigger files.

 

I'd like to link to this thread from one of the stickies. Can you please email me the pictures and I will resize them to a postable size.

-- Joe

 

Hmmmm

Nice idea, was going to build up stands at the corners and then maching them down

Have to see some pics of this!

later
Jeremy

 

Round bar stock welded on and drilled might be easier.

 

Was thinking either building the pads up or welding on round alum stock like you suggested Z69.

Angle cut it and then weld it to the base and drill it out.

later
Jeremy