L89/L88

[Noel O'Reilly]

I have been thinking about rebuilding the motor in my 68 L-89. However, also thinking of going with an L88 cam, headers, single 4 bbl. Does anyone have any thoughts on carb and manifold or thoughts on cam, valvetrain, ignition? Anything I should do as opposed to shouldnt (blueprinting, etc)? Anything else to do with the car while the engine is out?

Any thoughts, comments, criticism always welcome

Noel

[Duke W.]

Re: L89/L88

The L-88 cam is purely for racing and requires headers and open exhaust for the engine to develop full potential. Whatever the exhaust system configuration it has WAAAAY too much overlap for the street and will not be very enjoyable unless you plan to spend at least half your time between 4500 and 7000.

Your L-89 is an excellent high performance street engine and I would rebuild it exactly to OEM spec. Pocket porting and port matching the head will gain you 5 to 10 percent more top end power without impacting low speed performance.

I would also recommend that the engine be thoroughly "blueprinted", and leave no stone unturned. If you are not sufficienctly knowledgeable to do some of the work and manage the project yourself, I would suggest you seek out a shop that understands and knows how to do a BLUEPRINT STOCK rebuild.

Duke

[Noel O'Reilly]

Re: L89/L88

Thanks for the comments Duke....would you then suggest staying away from single 4 bbl and headers?

[Duke W.]

Re: L89/L88

A '68 L-89 is a rare bird, and it's value is best preserved by keeping it as original as possible. Unless you plan on serious racing, I would stay away from headers. They will make a bit more top end power, but they radiate a lot of head into the engine compartement and BB Sharks are marginal on cooling system reserve.

The trips can be finickly, but if set up properly they should provide excellet throttle reponse and their total flow at 1.5" Hg is about 906 CFM, which is plenty for a 427. There are specialists out there who do excellent restoration work on the trips and several on this board can give you a recommendation.

Duke

[Joe L.]

Re: L89/L88

Noel-----

From a maintenence simplicity standpoint, a 4 barrel carb is far superior to a 3X2 set-up. In my opinion, a single 4 barrel is just about always preferable to 3X2. On the other hand, changing an original L-89 with 3X2 to a single 4 barrel is foolheardy; the "pro" versus "con" balance sheet for such a change weighs HEAVILY on the "con" side. Far too much lost and very little gained. In addition, if you were to change to the complete L-88 set-up, including intake manifold, you would have to change your hood to the L-88 style. The ONLY 4 barrel, square flange (Holley) manifold with rectangular ports compatible with your cylinder heads which will fit under your existing hood is the 1971 LS-6 manifold, GM casting # 3963569.

For a STREET use engine, I wouldn't even consider using L-88 components, especially the cam and 12:1 compression ratio pistons. Completely out of the question. Period.

As far as headers go: forget it.