Gallileo60

Is there a way to tell the difference between a 5.7 LT1, and a 4.3 by just looking???? Thanks for the help...Tom

diablizzard

iTrader: (8)

it should be cast into the bell housing on the driver's side. do you have the vin that it is from?

camaronewbie

Uh .... isn't a 4.3 litre a 6 cylinder? An LT1 is an 8 cylinder.

TwiSSted

L99 4.3L (265 cube) V8. The "baby LT1" came in the 4th generation Caprice.

gwarren007

iTrader: (1)

L99 (4.3L)
A 263 in3 (4.3 L) was based on a 305 in3 with updated block architecture to be Generation II and a reduced 3 inches (76 mm) stroke. It was designated the L99, and was introduced in 1994 for the Chevrolet Caprice. It was externally identical to the LT1, but the bore was 3.736 inches (94.9 mm) and the stroke to 3 inches (76 mm) giving it a displacement of 263 in3. The pistons used in the L99 were the same as the ones used in the Vortec 5000, but 5.94 inches (151 mm) connecting rods were used to compensate for the shorter stroke. This was the standard engine used on all 1994-1996 Chevrolet Caprice Sedans. Including the Police Package vehicles.
Like the LT1, it features sequential fuel injection, reverse-flow cooling, and an optical ignition pickup. Output is 200 hp (150 kW) and 245 lb·ft (332 N·m). Due to its smaller displacement, it provides better fuel economy than the 5.7 L LT1, but at reduced horsepower & torque levels.

Gallileo60

Thanks for the replies..I will look on the back, this is in an old (60's) Grand Prix...I could not tell by looking.Might do my 89 good if its a 5.7.

torque_is_good

bring along a magnet

the LT1 from vettes and z28's had aluminum heads

Gallileo60

Hey torque, thanks for the info..

torque_is_good

just don't run a ground wire to an aluminum head and think it will be grounded

Gallileo60

Am leaning more toward a Vortec headed SBC, maybe a 383..Not sure..I think the LT1 would be more trouble than im ready for..Thanks again for the replies everyone...

torque_is_good

serious???? If it really is the 5.7 LT1 then thank the prior owner

a good tune, CAI, long tubes and you are well past 300 FWHP

Gallileo60

Hey torque, I know you are right..Just not sure I want to take it on right now..Will a vortec headed SBC not produce good numbers?? The main thing is, I already have a bus load of SBC boltons, and do not have any experience at all with the LT1 motor..Thanks for your reply..Tom

InfernalVortex

iTrader: (4)

The LT1 isnt worth the trouble... between the optispark and LT1 specific parts I'd pass.

I'd consider it if you had a healthy known good LT1 with a carb swapped onto it. Those things with just a cam can make some impressive numbers, but theoretically so can Vortec heads. The Vortec heads are actually better than LT1 heads.

Gallileo60

Im pretty set on building a 383 vortec headed motor..I will post it as it goes, should start in a month or so..Thanks for the input everyone..

KiLLJ0Y

iTrader: (1)

the LT1 350 block had the number "327" in raised form on the side of the block..

KiLLJ0Y

iTrader: (1)

the LT1 isnt a bad motor, granted it got a bad rap for the opti.. but most of the troubles of the opti come from contamination, and using cheap replacement opti's instead of the ACdelco or Delphi.

If you properly seal the cap with silicone, and use redloc-tite on the rotor screws, the opti is great. Or do the coil conversion LTCC like im doing

Considering the price of LT1's these days (i got mine from pan to intake with wiring harness and PCM OBDII for $650).. its not a bad way to go.. plus you can use your stock motor mounts, SBC headers, and some other parts which makes the swap much more affordable.

Gallileo60

I did not know the headers were the same...This one was complete for $150