CrazyHawaiian

Its finally time to get my 89 IROC-Z going again. While back the L98 blew up and this week I'm picking up the new motor. I don't know the exact year of this motor but its a 010 block w/ 2 piece RMS and a Holley 750 VS Carb setup. The thing is, I'm only familiar with the 87+ EFI stuff. I've done reading on the swap and I think I have a good idea of what I need to get this going. But I had some other questions that were more specific to the engine than doing the swap. I was hoping some of you more experienced guys could help me out with some questions about the older SBC engines?

First I got questions about Ignition. The new motor won't come with a distributor and I know my 87+ stuff won't work. I just want to verify the type of distributor I need to use. I'm pretty sure I need an HEI/Male style, but I'm not sure if I need Vacuum Advance or Mechanical Advance or both? The existing EFI stuff will be disconnected and hidden (not pulled). Do I need to goto an Aftermarket Ignition setup like MSD 6AL or something? Or will I be OK with just doing the HEI Distributor? On Summit I see a pretty good selection of HEI Distributors with all types of Advance between $99 and $150, brands like Accel, Mallory, and also the Summit Brand. Will those be OK?

My second question has to do with the 2 piece rear main seal and how that might affect the transmissions I wanna use. I know the flywheels/flexplates are advertised for 1 or 2 piece rear main seal, and the internal/external balanced also needs to be specified. But what about tooth count? Not sure if I'm gonna need a 153 tooth or 168 tooth flywheel. Does that only depend on what type of starter I'm trying to use?

My last question has to do with the engine accessories. I'm gonna remove the Serpentine setup from my blown L98 and try to install it on this older motor. I've seen a few threads on doing this, but no real detailed information. I'm guessing there's a good chance this won't be a bolt on deal. Does anyone know of a source for brackets that might make that swap possible?

Thanks guys!!

MrDude_1

your 87+ stuff WILL WORK, if you're keeping EFI.... (btw, it all just bolts on, except for modifying a couple bolt holes on the intake base with a drill.. nothing hard at all. unless you're keeping your current heads... then it all bolts together.)

if you're switching to a carb, then you need a non computer controlled distributor... you want a vacuum and mechanical advance one if you're going the normal cheapie route... you can also get an aftermarket all electronic one, or you can reflash your current stock stuff to work for ignition only.

really, any of the HEIs will bolt in and work. they're all interchangable.



you will need a diffrent flexplate (for a auto) or a diffrent flywheel (for a manual) but thats it. the bolt pattern on the back of the crank is diffrent.
once you have the proper flexplate, it all still bolts together...

the tooth count is the size. obviously if its larger or smaller, the starter has to move in or out to the correct size.. so yes, the starter is dependant upon it.
you dont need to change the size, but if you do, you'll need a new starter (or one that does both)



its a bolt on deal, unless you're using really really really so old its stupid to be using them parts... lol




really, its not anything hard... btw, id keep the EFI, and just ditch the TPI manifold for something better.

CrazyHawaiian

Hey thanks for the help! I was considering keeping the EFI but I just don't think my tuning skills are at the level where I can successfully re-tune the PROM for this motor. I got the tools but not so sure about having the skills hahaha. Its a 355 (30 over) with 11-1 high compression pistons and 72CC heads (don't have the head casting numbers yet but I'm guessing they are stockers). I don't know the exact compression ratio but the cranking compression for all cyl is between 210 and 215 so I know its up there. Motor also has an aftermarket cam, but the spec sheet was lost so not sure what kinda cam it is. I did get to listen to the motor before it was pulled and it sounds pretty good. I dunno, maybe I'm over-reacting about the tuning thing. But the guy that used to own this motor said he'd help me tune my Carb (and I got WB02), so that seems like the easiest and fastest way to get the car going. One thing for sure, not gonna be hacking the EFI stuff up, just gonna disconnect and hide everything as best as possible so if/when I decide to go back to EFI it'll be easy.

MrDude_1

do yourself a HUGE favor, both for underhood looks, and for your sanity.

go get a hacked up TBI(or anything) harness

you will want to change the coil power connector to the HEI connector.
you will want to get rid of the extra wires.


if you try to just tuck that harness away, not only will it look bad, but theres a good chance that it will rattle around/vibrate, and crack a few of the fragile-with-age connectors... its not that hard to disconnect it.


heres the basics of what you need:

HEI power..
Tach wire
Coolent Temp gauge wire
coolent temp for fan wire
relay setup for fan
relay setup for fuel pump
oil pressure gauge wire
electric choke wire
all the lights/horn and other non engine stuffs.

thats about it.


trust me, ive done this a few times before.. just get another bad harness and hack on that... dont try to just keep the stocker in there.. you will have to mangle it, or it will break or something.

as far as keeping the EFI... lets be honest.. the stock ECM is a PITA to tune compared with modern EFI tuning.... i dont want to touch a GM ECM anymore either... maybe if i had all of moates latest and greatest stuff, but honestly, if it was me, id either swap to a aftermarket ECM, or go carb too... with the exception of my LS1, all my previous PERSONAL swaps have been to carbs... for various reasons (money being near the top of that list)

CrazyHawaiian

Thats a really good idea, didnt think about that. I don't really care how the enginebay looks on this car, but you're right its not that hard to remove the harness when the engine is already out. I happen to be parting out two 91 RS's right now (both L03's). Think I'll pull the harness on one of em and give that a try. Thanks for the help again!!

I finally looked up the info on the heads and it was different than what I thought. The casting numbers were 378450, or I guess could be 376450 (thats the one that comes up), says its a head from a 305 w/ 60cc chambers. I figgure I might as well just slap it in and get it going and dyno it and see what happens. If its a letdown then I'm gonna try figgure out if I can use these 113 aluminum heads (L98 vette heads 58cc) on the older block. I happen to have an air-gap manifold that would fit those vette heads too. Right now I'm trying to decide on the Carb size, 650 or 750. Pretty sure I wanna use a Holley Carb with vaccum secondary. What you guys think?