I have an 89' RS with a 305. I have been wanting to do something with it because it lacks seriously in the performance department. I have been looking through parts books and such and everything I see for small block chevy's are for pre-86' engines. I am by no mean an idiot or an amature but simply don't know what was changes were made on the small block in 87'. I would like to know what some of the changes that were made are, as well as what kind of modifications I would have to make to use parts designed for pre-86' engines on my 89' 305. Any help would be greatly appriciated.

 

86 and later motors i know for sure had different head bolt padderns, There is a lot for your 89 TBI, I have a 91 and i have it running in the 14's with 130000 miles on the Od. Look in the tech articles on how to do the fee mods to your Throttle body, headers, cat-back, open element, wires, LT-1 cam, you can do a lot to that engine trust me, it is not worth it, doing all the work to get the pre-86 stuff on your motor. Also you have to look where you are from, if you are from cali, you cant use those heads, but it is all in you and what you want to do, but good luck and have fun with your ride.

Thanx
Dan

 

Over a period of time starting in the late 70s, the oil dipstick was moved from the driver's side to the pass side. This change affects the block, oil pan, oil pan gaskets and exhaust manifolds.

In 86 they changed from the 2-piece rear main seal design to the one-piece. This affects the block, oil pan, crank, and flywheel or flex plate.

In 87 they changed a few details about the heads, and added roller cams in some applications. The center 2 intake bolts on the newer heads go in at a different angle from the old heads, and the valve covers have their bolts in the center instead of around the edge. The bizarre roller cam setup they invented required new bolt bosses cast into the block to hold that goofy retainer thing they used, and additional holes in the front of the block for the cam retainer plate.

 

COOOOOOOOOLLLLL!!!!!!! somebody else from my area!!!

Pat you do have to deal with the muni's I.M. program... anything you get for that car has to have a C.A.R.B (california air recources board) exemption order (E.O. number)...

If you are thinking about changing the cam it could throw the tail pipe emissions out of wack if you go to big... headers must have all the provisions for the air injection, o2 sensor, and thermostaticly controlled air filter housing...

zroc

 

even if emissions are not a concern I would try to keep it as legal as possible... not sure about the 89 but I have an 91 formula, w/ an L03 (305 TBI), it has a roller cam set up... I want to put a bigger cam in like the genII LT! small block... short duration and medium lift (like .450)... I have to check around to see what all needs to be done (as in prom tunning) but its the beginning of the idea... I've got an intake for it and am planning on doing some mild porting to the stock heads...

what are all the particulars on your car??? ie, eng, trans, gears,

all your rpo codes should be in the center console and there is a decoder section on the main page...

zroc