lktna

OK I just bought a L98 out of a 1989 GTA a few weeks ago. I really don't know a lot about these engines. I have done some reading and know I have to have the valve guides milled if I use a cam over a .480 lift which will be done(looking at running the 847 cam), but I do have a few questions. My first question has to do with the flywheel(it didn't come with one). I will be putting the engine in a 1971 Nova SS with a M21 4 speed. Can I use a LT1 manual flywheel or does it have to be a L98 flywheel? My next question has to do with the distributor. With the engine being a roller cam and the distributor that I will be using came out of a flat tappet cam engine will I have to change the cam gear to make it work? And my last question is will the LT1 cam work in this engine? From what I have read it will but I want someone that has worked on these engines to conferm this. This is my first roller engine I have ever messed with. I'm used to the gen 1 small blocks but I want the benifits of the roller engine.

Thanks for your help,
LKTNA

SupplySgt.

As far as the flywheel you definitely want to use the L98 flywheel. The M21s were designed for 2 piece rear main seal engines (just like the older SBC motors) and the LT1 and above is a 1 piece rear main. As far as the LT1 heads are concerned I honestly do not know the answer, although personally I would chance it. The LT1 is a whole different animal from the L98 and so many of the components are vastly different. Now as far as the distributor, I would actually get an L98 distributor. Roller camshafts require a special gear on the distributor so that it doesn't tear the other one up. I hope what little info I have can help you out. Good luck.

lktna

The L98 is also a 1 peice rear main. I didn't know if the LT1 and the L98 were balanced the same or not. For now or at least the rest of this year I am going to use the L98 heads with a little port work and then I will change them out over the winter with an aftermarket set. So I will have to change my cam gear. I thought that I would but wanted to make sure.

super83Z

Yes you need the L98 flywheel. Change the dist gear definately!! I just went through this. The LT1 cam will fit no problem. The dowl pin may need to be ground down a bit though.

lktna

Thanks. I have been looking for a L98 manual flywheel. Seems they are kind of hard to find. LOL But I have a little bit of time before I will need it. Waiting on heads to come out of machine shop now. I still have my old engine in the car so have to get it out as well. So there is time. LOL

super83Z

Well the L98 never came with a manual in the F-body. I don't know if the Y-ody one would work. You may have to look to the aftermarket, such as centerforce, to find the flywheel that will work for you.

cnorton

I don't think the original poster asked this question but, just in case, LT1 heads will not work on an L98 block without a lot of extra work. There are much simpler ways to get the benefits of improved cylinder heads without the expense and hassle of this conversion.

c

quickchicken

i second this!!!!!! worked at COMP for the past 5 years and thats one thing alot of folks dont know is to change the diz gear with the cam. a poly gear would work super and can be had thru COMP. mic your diz shaft and see if they have one. a stock GM diz shaft is .428 oor so and the smallest poly gear they have is a .490. i had one of my cam shop friends cut me a sleeve and it worked like a champ.

as for the flywheel, i had issues. a GM tech friend told me the flywheel is balanced specificlly to that motor. i found this out when i bought an exact stock GM replacement flywheel. dang near rattled my fillings out.

lktna

OK? So maybe I just need to buy a new balanced assembly with the balancer and flywheel included? I thought the stock HEI dist was a .491 but I could be wrong. I can go with a bronze gear since the car will not be drove all of the time. Mostly just comes out on the weekends to play on a Friday night and back in the shop Sunday night with a trip here and there to work.