AGD3000

Quick question: are they a straight swap?

Ive got a UCF10 1991 ls400 with a slightly noisy engine.

I also have access to a cheap UCF20 front clip.

Much thanks

acidfire52

No. complete redesign.

trukn1

As far as the engine, it WILL drop right in (sizewise), but you will have other problems to deal with. THe wiring is different, the ecu is not the same as well as a host of other wiring dilemas. If you plan of re-wiring the entire car for the new engine, then you are looking at ALOT of work to do so. The simple answer to your question would be NO, they are NOT a straight plug and play, drop in swap. The second gen (Ucf20/21) is also an interferrence engine with variable valve timing, whereas your first gen is not. What this means,,, snap a timing belt on a later model engine, and you WILL cause alot of damage to the motor, pretty much the motor is toast. The older LS engines (89-94) did not have VVTI and were not interference. Snap a belt on one of these and it was considerable less damage. Not to mention, the older motors had stronger internals than some of the later models. Best advice,, if your car is worth it, and you plan on keeping it for awhile, just get YOUR engine fixed, or find another in the similar year as yours. THIS WILL be a straight swap. FRONT CLIP from the later model,,,, is possible, but only with ALOT of body work and a fairly large cash source to accomodate the work. In the end not really worth it.

PureDrifter

iTrader: (10)

^this pretty much sums it up.

AGD3000

Awesome info! Many thanks Sir.

After reading up a bit more its probably just a valve clearance issue. The noise is a ticking sound.

So Im planning a valve clearance adjustment.

steve2006

Valve clearance adjustment is quite a major job on these engines.

http://www.lextreme.com/valve_clearance.html

PureDrifter

iTrader: (10)

less major than swapping engine/trans/driveshaft and rewiring the entire car.