ok, i have the L69 with 4bbl carb and right now i don't have the money to buy the creat engine i want...so i was thinking of finding a complete L98 and rebuilding it. but i'd like to know if i can use the intake and carb off my 305 and if it would work with my ECM. to a point, it would be the same everything but with a larger engine...could this work??

 

It'll work. For awhile, the factory offered a kit that put a ZZ4 350 under your carb (although the intake manifold came with the engine).

If you get a real L98 (unless it's a Vette L98), the center two intake manifold bolts on each side will be at a different angle than the others - elongate the intake manifold bolt holes to get it to fit. And, it will have a one-piece rear main seal, which requires a different flexplate/flywheel than yours has.

Otherwise, minor carb secondary tuning will be all you need.

 

well that's good to know. what if i got an intake for the L98 that will use my carb. and the stock L98 flywheel will work tho?? also, what kind of minor carb secondary tuning is needed??

EDIT: i can use the stock ECM, right?

 

you need to get new metering rods and a new hanger, this gonna cost aroung 10$ total and some one else can prolly tell you what size they should be, basicly makeing the secondarys open sooner and flow more fuel for the increase in cubic inches.

about the l98 fly wheel, that should work, you are changing it because a 2 piece rear main seal motor and one piece motor have different fly wheel mounting designs...

 

l98 never came in camaros with manuals. only automatics you have to go after market.

 

I did the same thing over 10 years ago - took an L98 longblock and swapped it in for my LG4 - worked fine with the right tuning.

A few words of advice before you make the swap:


Either leave the stock roller cam in or swap for a replacement roller - flat tappet cams will cost you too much power.

Do not under any circumstances run a block fuel pump, put an inline electric by the tank and regulate the pressure by the carb.

Expect a stock TH700R4 to last about 15 minutes under the torque of a 350 - even driving "normal".

Do buy headers, a 3" cat, and a 3" cat back exhaust if you don't have them already.

Do buy an a/f guage and tune the secondary metering rods and hangars using it.

Find an Edelbrock Micro-plus timing computer for the LG4/L69 motors and install it - it works wonders.

Since the L98 motor uses a reverse rotation water pump, it must be replaced - replace it with an aluminum pump to shave off 7-8 lbs.

It is a lot easier to swap cams and have heads done when the engine is on a stand than it is in hte car - so if you want to, do it before you install.

Stock flywheel should work.

Buy a lightweight starter if you need one.

You will need to change the oil pan if the motor is out of a Corvette - use a Hamburger pan and rubber gaskets - cork leaks.

Intakes - Corvette L98s use the same intake as a stock LG4, F-body motors use the "different" bolt pattern intakes. Buy an Edelbrock performer intake. EGR valve won't clear centerbolt valvecovers - buy an adapter or toss it.

Clean out the engine bay before you install your new motor - degrease and paint (if necessary).

 

Irrelevant. L98 and LB9 flywheels are interchangable within a given model year. A stock LB9 flywheel will fit an L98. But, he doesn't have a manual tranny, anyway.

The year of the engine is important. '86-up have the one-piece rear main seal. '85-older have the 2-piece. Most L98's, and all 3rd gen L98's, are of the one-piece variety.

There's nothing particularly wrong with running a mechanical engine mounted fuel pump. The factory did it for every carb'd car they built. It could be argued the electric is "better" (the factory provided one for the ZZ4 conversion kit), but that doesn't make it necessary. However, some of the later L98's didn't have the mechanical pump mount finish machined.

 

IMO its better to run a mechanical pump instead of electric with a carb. Its what I always do.

 

As for tuning, you can always use the ZZ3/4 binary for an auto or manual and with or without the ESC system. Of course, you can always custom burn to your specs, so many variations can be supported.