LT1 Engine

[SSDan]

I have just bought a 1946 Chevy truck with a 1995 or 96 LT1 engine that came from a Camaro with aluminum heads! My question is it is stock and I would like to give it a little more pep. I notice Summit has two different size throttle bodies, a 52mm and a 58mm. What is the difference other than size? Why would you want the smaller size?

They also have a air fuel ratio sensor from Granatelli. What does it do and will it improve performance over the stock unit.

I know the engine has a reverse flow fan driven off of the cam. Would there be any benefit to go with an electric Meizere Fan? I have called them and they say they have one for the LT1.

Any other ideas would be appreciated!

Dan Masheck
Wharton, TX

[paul67]

Thought the alloy headed 1's were vettes and LT4's .

[Lawrence]

Hi Paul, hows yours getting on? Ally heads on the Camaro too, I have them on the '55 and the '68 has them on its new motor thats going in after Christmas.

Dan, can't see how you could have a cam driven fan as thats where the water pump is on an LT1? Have you got any pics of the motor?

[TPI Monte SS]

I know the engine has a reverse flow fan driven off of the cam. Would there be any benefit to go with an electric Meizere Fan? I have called them and they say they have one for the LT1.

I believe that fan is actually driven off the crank pulley if you look closer. The LT1 Caprices (NOT 9C1s or Impala SSs) had that setup you're talking about. Electric fans would really make the engine bay look cleaner, and probably free up a few hp. You won't give up anything over that setup as far as cooling the motor down though.

[camcojb]

I have just bought a 1946 Chevy truck with a 1995 or 96 LT1 engine that came from a Camaro with aluminum heads! My question is it is stock and I would like to give it a little more pep. I notice Summit has two different size throttle bodies, a 52mm and a 58mm. What is the difference other than size? Why would you want the smaller size?

They also have a air fuel ratio sensor from Granatelli. What does it do and will it improve performance over the stock unit.

I know the engine has a reverse flow fan driven off of the cam. Would there be any benefit to go with an electric Meizere Fan? I have called them and they say they have one for the LT1.

Any other ideas would be appreciated!

Dan Masheck
Wharton, TX

58mm is the normal size to step up to when modding, but would make very little difference on a stock or mild combo. With a cam swap, ported heads, and headers then yes, otherwise spend your money in another direction.

That engine uses an electric fan. Meziere has an electric WATER PUMP, which would not add much power again for the money.

The wideband a/f kits are useful for tuning, the narrow band type are not accurate enough for wot tuning. Best bang for the buck to wake the engine up would be headers and exhaust, tuning, cam, and then ported heads. Start with the exhaust and tuning , then cam, then head and cam if the budget fits.

Jody

[WS6]

I agree with Jody. The electric water pump does help a little powerwise, but it is not worth the money or effort. Besides, unless you wire in a warning light, how will you know if the pump is pumping? I would however not step up to a 58mm throttle body. Unless you are going forced induction or larger cubes, the 52mm is plenty and it doesn't require opening the intake throttle openings like the 58 does. So you can swap it on in the driveway easily. Headers definetly wake these engines up. Don't be afriad of catylitic converters in the exhaust system either. A pair or single Random Technology cat will not rob any power. That's just an FYI if you have any emissions requirements.

One thing you do need to determine is if you are a 95 or 96. That is mainly because of the ECM not the engine. 95 was OBDI and 96 was OBDII. It will matter when it comes time for tunning. Aside from that, the 95 and 96 are virtually identical mechanically.

[SSDan]

The fan is driven off of the cam. I believe there is a direct link type drive.

Here are a few pictures of the engine. I hope they help!

Dan

[Samckitt]

I don't see a fan. On the LT1, the waterpump is driven off of the cam gear. The optispark is direct driven from the cam. Most LT1 engines have an electric fan(s). Some B body cars had a setup where an idler pulley is where the normal pulley is for the waterpump. And the fan is driven by the serpentine belt.

[Samckitt]

By "fan" are you referring to the impeller in the waterpump?

[SStrokerAce]

Do some reading over at camaroz28.com in the LT1 section if you need some help on mods of this motor.

Bret

[Lawrence]

Hi Dan, Nice truck! Looks like the fan is off the crank (the cam is where that ribbed ally cover on the waterpump is, just under your inlet elbow). Both of my LT1's had factory electric fans that are controlled by the engine PCM, so I guess yours wont have the wiring in place to do this if you have used a factory loom?. You can use any electric fan(s) that will fit, and either control it from a temperature sensor in the coolant or a switch on the dash. It may be possible to add the two control wires from the computer and re-flash your PCM to enable the fan control as well if you wanted, not sure to be honest.