TPI to LT1 Conversion
Thread Starter
Instructor
Joined: Dec 2009
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From: Houston Texas
TPI to LT1 Conversion
Hi, I have a 1989 corvette with TPI 350 sbc and Im trying to go through with the TPI to LT1 manifold conversion. So I am pretty understanding about everything besides the destributor. I am wondering how do I locate the hole to bore into the manifold for the destributor to drop down through? Im also wondering what the deal is with the wedge plate that needs to be set under the destributor. My main goal is to understand and mark everything out so I can give the manifold to the machine shop and let them do all the work, Please HELP!! 
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
You need to make a pattern ( template ) from a reg intake to position dist hole in LT1 intake
Wedge is need to get correct dist height and angle; compare reg intake with LT1 at the dist location
Wedge is need to get correct dist height and angle; compare reg intake with LT1 at the dist location
Thread Starter
Instructor
Joined: Dec 2009
Posts: 236
Likes: 0
From: Houston Texas
thanks, I was wondering if you know of any cheap manifolds I could pick up off craigslist that have same bolt pattern as the TPI that I could use to make the templets rather than pull the TPI manifold and have a disfunctional corvette while I make the lt1 manifold.
Race Director
Joined: Nov 2003
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
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Camaro and Firebird TPI's and all earlier SBC manifolds are going to have the dizzy in the same place. That's where it's designed to hit the cam gear!
After you do this, make sure the distributor height is correct. (Make sure the dizzy isn't clamped HARD against the cam gear. That's causes accelerated wear.)
Or you could do it yourself. Mark, punch, and drill with smaller bit first. Even if the hole isn't exacly perpendicular (up/down), you should still be fine. You just need access to the cam gear and a tight seal on top of the manifold (besides enough height).
Last edited by GREGGPENN; Jul 4, 2010 at 12:22 AM.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
For the intake bolt pattern change you only need a gasket; if you pull your dist out you should be able to make a template of dist location in relation to the bolt holes
Race Director
Joined: Dec 2006
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I've never done this but was thinking that if the OP were to make the hole in the intake close enough it could be a bit bigger than needed. It would not have to be exact. The spacer could have a hole in it that is the exact size. With the LT1 intake on the engine he could install the dist through the spacer and move it side to side and front to back since the hole in the intake is bigger than needed. When it is lined up just so he could make witness marks on the spacer and intake. Then pull the intake and clamp the spacer in the marked spot and have it welded in place. I'm thinking the spacer could act both to hold the dist at the correct height and serve a similar function to a fender washer. What do you think?
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
With the LT1 intake on the engine he could install the dist through the spacer and move it side to side and front to back since the hole in the intake is bigger than needed. When it is lined up just so he could make witness marks on the spacer and intake. Then pull the intake and clamp the spacer in the marked spot and have it welded in place. I'm thinking the spacer could act both to hold the dist at the correct height and serve a similar function to a fender washer. What do you think?
That is the preferred way.In many of the early LT1 conversions guys didn't have access to a alum welder so they used the spacer and commonly had oil leaks
Last edited by rodj; Jul 4, 2010 at 02:07 AM.
Team Owner
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just a though. I am glad I quit while I was ahead.
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Thread Starter
Instructor
Joined: Dec 2009
Posts: 236
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From: Houston Texas
Ok, now im kinda interested about the mini ram, but I still want to do it on a budget. So were do I begin looking for a used one. I looked at their site and they go for about 1000 bucks but they also have many models under 1989 (or l98 engine), which should I look for to put in my Vette?
Drifting
Joined: Feb 2006
Posts: 1,423
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From: Magnolia Tx
measurements. ANY sbc intake will work for measuring.
