LT1 manifold adaptation (was question)

["SPECTRO COATING CORP." <spectro@ma.ultranet.com>]

Shannen and I have been trying to adapt an LT1 intake to a Vortec equipped
SBC right now - here's what i can offer...

1) bolt pattern - in looking, it appears that is the least of our problems -
the Lt1's 72 degree intake bolt angle appears to leave plenty of mat'l to go
either way (conventional sbc or vortec) however if you choose to put the
intake on a standard set of heads you're going to have trouble with
clearance for the drills - yes - it can be drilled from the backside, but I
think you'll still need to mill on the topside to get a decent seating
surface for the bolt heads. Can be done, but you'll need a special backside
spotfacing tool to do it. In this case using the vortec heads does help.

2) Water passages - differences have been covered by other posts on this
topic - how to get around it? You could drill and tap the the front of the
heads and then use one of the remote thermostat housings - OK - if you
aren't running late model accessory drives - if so then we need to come out
of the intake face.

This is where it starts to get sticky - if you look closely at the TPIS
miniram they have set the TB back a couple of inches to gain clearance for a
water passage and the thermostat housing. So far we're still undecided how
to get around this problem. Current ideas include boring down thru the top
side to meet the water outlets in the heads (Reasonably Possible) then to
insert fittings for a remote thermostat. This causes all sorts of fits with
the throttle linkage, though.

Another possibilty (Remotely Possible) is to bore a passage completely thru
the intake side to side so as to insert  "T " shaped tubing that would allow
water to be pulled out below the TB.  Some of this piping would have to be
done with fittings as there is no access to weld it together. Using a L98
IAC housing will help to gain a little clearance around the bottom of the TB
where the water outlet(s) will be

We have looked at shifting the TB back  like the TPIS intake - Still
thinking, not sure how to handle it, but it isn't a simple milling job -
you're into idle air/egr passages when you do this. Plus welding in a new TB
mount and all of the associated water transfer.

3) - the distributor mount, not a huge deal, as it appears the small cap
dist will clear the back of the plenum (at least if you remove the EGR - use
an LT4 EGR blockoff plate) but the casting may have to be somehow reinforced
in that area before a proper mounting can be obtained. And - OBTW - look
closely at a standard manifold -  Chevrolet distributors are not mounted
perpenticular to the end rails - they are at an angle. Just to make it
interesting.

Lastly - note that you're going to have a good time trying to get your
reference points squared away - there's not much on the LT1 that truly
corresponds to a conventional SBC. What i mean to say here is that to ensure
that we get the bolt holes in the right position, we have to pull the
existing vortec intake off the car to get it on the milling machine (or
CMM - if you have one laying around ;) to try to find out where everything
has to be drilled. Even then there is going to be some best guessing based
on the raw casting surfaces.

I know this is kinda long and probably discouraging but I thought I should
try to explain just how involved its going to get before you lay out the
long green and then find out you are over your head.

Hope this helps - Jason