[AlK2MT]

Hi forum. This is my first post. I have a 1974 Chevy Impala that I am working on. It is 100% original. It was my mom's first car and she drove it 100, 000 miles and parked it in the garage. It hasn't seen highway since 1985 but it has been in a heated garage for all these years so everything is in good shape. I am wanting to give it some hot rod treatment in the engine department as the final touch. It has the stock 350 engine and TH350 heavy duty transmission. Basically I want to give it the SS treatment what GM should have done back in 1974. So.. any help on an engine build would be helpful. I want it to look fairly stock.. I have rams horn manifolds for it and a Rochester 4 barrel carb... as far as intake, cam, heads and everything else.. I have no clue. I know that I want good torque and general performance.. it doesn't have to be the fastest ever.. it's a big car.. but it would be nice to have some pow pow when needed.. maybe a little extra. I plan on going dual 2 1/2 inch exhausts out the back with an exhaust cut out after the cats and... I bought a dual inlet ram air box that I want to use as well. So any help would be awesome. Any parts recommendations, advice... etc. welcome. This is my first hot rod ever and I am having a lot of fun. Its a car not many people have and I think its a great project. Thanks.

[MI2600]

By 1974, GM had downgraded their hp to ridiculous levels, which included the compression ratios. That's going to limit your attempts to build any high hp.
The car is pushing 30 years old and you're right, it's heavy. I know what it's like to want to have a powerhouse, but if I were you I would concentrate on keeping it all original.
If you're intent on having a fast car I would build another engine and keep the original engine to restore it in the future. I know that's not what you probably wanted to hear, but there aren't many 30 year old cars that haven't been cobbled up. Good luck with whatever decision you make.

[Fox75]

nice car, we don't see many over here. Anyway what do you mean by heavy duty transmission? who told you that? the first thing to decide when building an engine is it's intented use, is it a daily driver or a weekend car, are you intending to take it on the track and is fuel consumpton an issue. Do you know what diff gears you have? post back and i'll point you in the right direction

[4 Jaw Chuck]

Give it a nice factory style rebuild and enjoy it for another 100 000 miles, an early LT1 cam would sound good too.

[AlK2MT]

Originally posted by Fox75
nice car, we don't see many over here. Anyway what do you mean by heavy duty transmission? who told you that? the first thing to decide when building an engine is it's intented use, is it a daily driver or a weekend car, are you intending to take it on the track and is fuel consumpton an issue. Do you know what diff gears you have? post back and i'll point you in the right direction

Let me code it out tomorrow and I will let you know on the diff. I don't remember off hand. The transmission is a heavy duty transmission with an extra transmission cooler system....GM installed them on only a few models in 74 special order. My mom used to have the car hitched up to a small 1 horse trailer and she ordered the tranny as a special option. I have the original order papers and the window sticker. Medium Blue Metallic, 2 door sport coupe, A/C, Heavy duty transmission, AM radio, factory jack and spare kit. Anyway. It's a classic and has a lot of emotional value to the family so we kept it original. I have no intents of cutting it up or anything like that.. I just wanted to improve the performance a little bit as a daily/weekend summer driver and maybe go to a few shows. I figured this website must be a good resource.

[AlK2MT]

Originally posted by 4 Jaw Chuck
Give it a nice factory style rebuild and enjoy it for another 100 000 miles, an early LT1 cam would sound good too.

Factory style rebuild... so just leave it the same... what about a new carb? manifolds? dual exhaust?

[AlK2MT]

Originally posted by MI2600
By 1974, GM had downgraded their hp to ridiculous levels, which included the compression ratios. That's going to limit your attempts to build any high hp.
The car is pushing 30 years old and you're right, it's heavy. I know what it's like to want to have a powerhouse, but if I were you I would concentrate on keeping it all original.
If you're intent on having a fast car I would build another engine and keep the original engine to restore it in the future. I know that's not what you probably wanted to hear, but there aren't many 30 year old cars that haven't been cobbled up. Good luck with whatever decision you make.

Well more than likely I will probably do a factory rebuild like another poster suggested... probably add dual exhaust and a 4 barrel carb and new manifold.. that was available for the LT-1 Corvette that year and leave it at that... overall I am really content with everything else. .and have put a lot of work in to keep it original..... I wish GM hadn't done the downgrade thing.. but with the oil shortage and the stress from new compact cars.. I guess they had to compete.... who knows... its a fun car.

[mikeweyman]

if it is not to be a muscle car, why rebuild? is it smoking?my vette has 150,000 miles on it and when we broke down the engine,there wasnt a single scratch on the cylender walls.the guy told me that i could get another 100.000 on it as a daily driver.but thats not my intention.if i was you, maybe take another block, and do it up and use it.when your all done and going to sell, put the motor back in. my 2c. mike

[jimfulco]

Might want to rethink the LT-1 solid cam in a heavy car with low compression & probably highway rear gears. It'd sound cool but wouldn't run worth a flip. I'd do the duals, 4bbl., maybe a Performer intake & a mild cam (RV-type). Since I know you observe the MT speed limit at all times (I always did), you should consider looking into better tires & some sway bars. If you decide to rebuild, get some modern cylinder heads & pistons instead of the inefficient 1974 smog stuff.

[AlK2MT]

Thanks for all the suggestions so far. I think I have a pretty good idea of what I am going to do with it. Duals, 4 barrel, intake manifold, mild cam, new Eagle GT's. I think it will be fine. I have to replace seals and gaskets for everything as well. Thanks for the help.