Thread: LT intake manifold modification for distributor

Tweet

submit

That is a neat mod! Can you show us the finished manifold and maybe the dist mounting piece you weld in?

I'd like to see the finished deal too. There are a lot of LT guys that would probably love to have this mod.

Just curious. Did the LT1 manifold survive the surgery???? Street rod engineering at it's best!

WoW-going on 2 years---------


Did 3 manifolds back when these pics were done-


Just last week end a guy brought in another one for me to do so after I finish up re paneling my garage door it'll be cleaning core and making chips and welding-I'll try to get pics of the finished job and some of the different dist that have been used---not a lot of room for the big cap hei like thingies

The multiple chamber openings you cut into made me wonder if this was doable. Not sure what each was other than the egr, but thought this might take multiple patch pieces to make it work. If you were able to get a clean finished look, this would be quite an impressive mod to say the least.

Or, for about $300 - http://www.summitracing.com/parts/NAL-24502592/ Seems to me that the machine shop costs would be equal to or more, but I may be wrong. Of course when you're doing the machining it's a different story, as your rates for your own work can be zilch.

Duece4------I usually get a clean, finished look to any mods I do on my stuff


Roger-------the manifold is a way to go if a person wants to just put a carb on an LT1 for some other era car, but the costs are a lot higher than the $300 ------you will need a carb, air cleaner, fuel pump and lines, regulator,etc plus of course the complete ignition system-a person going that route will be spending maybe as much as $2500?----


Now , not to say that he won't be spending $$ on this conversion, but it does allow the keeping of an excellent EFI system and basicly just getting rid of the opti. I myself never had any issues with an Opti but I want to move it out to get rid off the wires down there so I can mount the alt and a/c close to crank area-- However, on my wifes 33 I did move the engine back toward cowl for more room behind radiator and its tight where the dist goes----but the driveshaft is shorter!!!!!!!!!!!!!!!!

Originally Posted by jerry clayton

....Now , not to say that he won't be spending $$ on this conversion, but it does allow the keeping of an excellent EFI system and basicly just getting rid of the opti. I myself never had any issues with an Opti but I want to move it out to get rid off the wires down there so I can mount the alt and a/c close to crank area-- However, on my wifes 33 I did move the engine back toward cowl for more room behind radiator and its tight where the dist goes----but the driveshaft is shorter!!!!!!!!!!!!!!!!

I'm not familiar with the opti-spark distributor system, but as I understand it inputs to the PCM for crank position (laser through disc w/360 tiny slots), and the PCM then triggers the output to the coil based on the spark map that's in the PCM, and also triggers the injector pulses based on this crank position input, right? When you make this change you'll use an electronic distributor, but what do you do for the crank position sensor? Sounds like a neat modification, and I expect I can find out about it on the hot chevy sites with a little Google mining but it's lots easier to ask the guy who's done it before.

Originally Posted by jerry clayton

Duece4------I usually get a clean, finished look to any mods I do on my stuff


Roger-------the manifold is a way to go if a person wants to just put a carb on an LT1 for some other era car, but the costs are a lot higher than the $300 ------you will need a carb, air cleaner, fuel pump and lines, regulator,etc plus of course the complete ignition system-a person going that route will be spending maybe as much as $2500?----


Now , not to say that he won't be spending $$ on this conversion, but it does allow the keeping of an excellent EFI system and basicly just getting rid of the opti. I myself never had any issues with an Opti but I want to move it out to get rid off the wires down there so I can mount the alt and a/c close to crank area-- However, on my wifes 33 I did move the engine back toward cowl for more room behind radiator and its tight where the dist goes----but the driveshaft is shorter!!!!!!!!!!!!!!!!

A dumb question for you Jerry, could one work a crank trigger system onto an LT engine? I love their simplicity and easy of adjustment on the timing! Just curious and wondering if you have done one?

I thought I might throw my 2 cents into this conversation. I always read gen 2 LT1 stuff when posted because I own three of them. Two run('94 Z28 Camaro, '97 SS Camaro)and the third is going into to a project truck('57 Chevy) if I ever find the time to finish it.
As far as the optispark distributor, On the '94 I've changed the distributor twice in 110k miles. It has the older non-vented design which crap out at roughly every 50k miles. The last one I put in was a newer design MSD that includes venting and has gone about 10k miles trouble free. I also have an MSD unit on the '97 that is trouble free.
With regard to Dave's question, I have been considering going to a crank triggered coil on plug system in the '97. Not because the optispark is problematic but because it would allow me to use a PCM that is way more advanced than the original '97 PCM along with the precise spark energy and accuracy of coil on plug.
I know a engine tuner that told me the LT1 PCM's are dinosaurs compared to the newer LS PCM's in the sense of being smarter and faster. Makes tuning a big cammed LT1 possible. Here's a link to a setup I'm considering buying from what seems to be a very innovative company. A plug and play setup that can be done in a day.
https://www.torqhead.com/how-it-works.html
Nolan

Originally Posted by JOATMON

I thought I might throw my 2 cents into this conversation. I always read gen 2 LT1 stuff when posted because I own three of them. Two run('94 Z28 Camaro, '97 SS Camaro)and the third is going into to a project truck('57 Chevy) if I ever find the time to finish it.
As far as the optispark distributor, On the '94 I've changed the distributor twice in 110k miles. It has the older non-vented design which crap out at roughly every 50k miles. The last one I put in was a newer design MSD that includes venting and has gone about 10k miles trouble free. I also have an MSD unit on the '97 that is trouble free.
With regard to Dave's question, I have been considering going to a crank triggered coil on plug system in the '97. Not because the optispark is problematic but because it would allow me to use a PCM that is way more advanced than the original '97 PCM along with the precise spark energy and accuracy of coil on plug.
I know a engine tuner that told me the LT1 PCM's are dinosaurs compared to the newer LS PCM's in the sense of being smarter and faster. Makes tuning a big cammed LT1 possible. Here's a link to a setup I'm considering buying from what seems to be a very innovative company. A plug and play setup that can be done in a day.
https://www.torqhead.com/how-it-works.html
Nolan

Thanks for the link, great information there, looks like a fine product!

I have mounted both the a/c compressor and alternator down low on my engine. I can see where the opti spark dist would interfere with this. I don't think I could have found enough room for the LT1's extra length over the short water pump setup, but for some builds that require the low mounting, the reverse flow and TPI might have been worth all the manifold fab work. Going from a manifold shown in Jerry's post to a functional manifold is quite a leap to make.

Roger-basicly this just moves the rotor/cap part to the rear of manifold--with the later years LT there is a more modern sensor in the timing cover so that and the fact that the 1996 and up ( on all vehicles OB2) are much more advanced than the early ones-----I think that most of the problems people had with opti was self induced-washing engine with high pressure washer, etc-also there was a vent system tied into the intake manifold and air cleaner so clean dry air would circulate but when pepes put fresh cold air intakes, etc , etc they lost the oem system of the vent-then the heat/cool cycles probably created a vapor/condensation issue-------My distributor will just be a rotor/cap with the coil, timing functions still done by the PCM.
However I am doing one for a guy that is taking off a coil/plug like the new LS engines as it didn't meet expectations and he will be doing his with a FAST XT? instead of the oem-(oem is limited to 6 or 7000 rpm)


Duece, if you haven't changed the intake or exhaust its not a hot rod??????????
I believe that the LT water pump being driven from the cam is more compact than the older engines by eliminating another pulley. the issue with my install into my wifes 33 is that now that we want to add a/c, we need something on each side of the crank and to lower them (alt, a/c) enough to clear the wire terminals of the opti gets down low and close to steering stuff. I have thought abought driving alt off tail shaft but if we run air will need more amps/mile and in slow moving traffic probably wouldn't keep up. If you have looked at front of LT1 engines, keep in mind that there are different length lower pulley/dampners from various installs-vet, Camaro/firebird/buick/impala/etc

Looks like there are several LT1 intake mods going out there. Opti Spark to dist with several paths taken from plugging holes to major milling of material and adding plate along with dist mount shim being welded in. Others are modifying LT1 intake to fit SBC first gen. Wow. There are a few photos of modded intakes out there. Some are very well done; others not so much for looks but probably work fine. Neat stuff for sure!

So if I understand what you're saying, you're leaving the low voltage part of the optispark (PCM inputs) in place on the front, eliminating the cap & rotor, and installing a stand alone dizzy in the back for the HV function? I agree, most of the opti problems seemed to be self induced by power washing....