350 engine project advice

Discussion in 'High Performance Modifications' started by 79sportcoupe, Jan 30, 2018.

  1. 79sportcoupe

    79sportcoupe Member

    Nov 22, 2011
    The girlfriend and I have a 79 z28. The car runs, but needs a good bit of work. I cannot get interested in the project though until the thing is fast and fun to drive. I am used to light cars, these 2nd gens are anything but that. I am looking for some advice.

    The car has a motor that does not burn oil or do anything funny really, it has good compression, even between all the cyls. but it is a low compression motor put together in the 80's out of spare parts. It has a 650 holley, and headers, and a decent intake, but has a dog of a rv cam (don't know specs) and the car is totally gutless. It won't even spin the tires on dry pavement. I had a 2nd gen myself awhile back and it had a junk crate motor in it that did not make much a ton of power either, but it had a steep rearend gear (maybe 4.11). That car was fun but sucked on the hwy. I want to stick with the 3.42 since it is a good compromise and already there, I don't want to put money into that. I am trying to figure out how much power I need to match the "fun" factor the car with the deeper gears had. I know that is probably hard to do.

    I don't mind sticking some $$ in the motor, but obviously past a certain point there is a lost cause. I was thinking about maybe a 10" 3,000 stall, somewhere around a 270 cam and up the compression to maybe around 10:1 I have someone helping me do the engine work and they suggested porting the heads I already have since they know someone good at it. I know many here have built tons of motors. I am not looking to win at the dragstrip or race new 400hp cars, but is it going to be fun enough to be worth it? (or should I just save a extra couple grand and go with a 400hp crate motor). I know I only get one shot and don't want to waste my money for sure. Any advice is appreciated!
  2. larrylarry

    larrylarry Veteran Member

    Dec 22, 2011
    San Antonio Tx
    Buy a crate motor with no less than 400 hp or do a total rebuild of your engine. The price between the 2 is close, maybe 3 or 400 hundred dollars for the crate motor. Best advice is to buy one of David Vazard’s books for Chevy engines an pick one of them you like to build. Don’t throw a bunch of new parts into an engine without a recipe to go by.
    Last edited: Jan 30, 2018
    djorgensen3 likes this.
  3. Led Zep

    Led Zep Veteran Member

    Mar 13, 2008
    Do not waste your time porting smog heads.Get a good set of aftermarket heads.Head/cam combo is where it is at,and with a 3:42 gear,it is not a dog.
  4. Mwilson

    Mwilson Veteran Member

    Id look into some summit, jegs or Blueprint heads economical and will make a huge difference and something like the 268 XE cam or a lunati voodoo maybe
  5. tom3

    tom3 Veteran Member

    Aug 1, 1999
    I'd spend the money on heads too. That RV cam might really wake up with some compression and improved air flow. A set of 1.6:1 rocker arms might add a bit too. Not sure about that high stall converter on a mostly stock street engine.
  6. Zspoiler

    Zspoiler Veteran Member

    May 6, 2012
    Federal Way, Washington
    I would suggest a crate engine from Chevrolet .You have a variety of horsepower rating to choose from.Plus you have a warranty.I have a 290 HP 350 in my 1981 El Camino SS.Its my daily driver and its fun to drive. Then you can put the stock one under the bench in case you want to restore the car .While pounding on crate engine.It all depends on your pocketbook and what you want to do with the car.
  7. cadillac_al

    cadillac_al Veteran Member

    Apr 22, 2015
    A stock 350 should burn tires on a Camaro. Your 350 must have the wrong timing or wrong cam or carb that is not optimized. If I bought it I would put in a decent cam (voodoo 260-262) and put a carb on that I can work on and tweak the timing. I'm not a Holly guy but i would like to play with one someday. I just don't want to spend $500 for a new one. The crate engine is the easy way if money is no object.
  8. 79RedZ

    79RedZ Veteran Member

    Mar 24, 2009
    When you say a decent intake. What kind? Dual plane or single plane?
  9. vegas1974z28

    vegas1974z28 Moderator Staff Member Lifetime Gold Member

    Jan 10, 2002
    Las Vegas,NV
    2 words...

    Big Block
    PalmbchZ28 and Mwilson like this.
  10. 79sportcoupe

    79sportcoupe Member

    Nov 22, 2011
    Thanks for the advice so far! I want to add a bit of info. The intake is a aftermarket intake but not a high rise, everything fits under the stock z28 hood. I will get more info on it tonight. First thing I want to point out, is this is NOT the original engine (so nothing to "put back and save for value". It was long gone by the time I got the car. The guy I bought the car from, had a buddy evidently that built motors for people. He put the motor together for him pretty much at cost as a favor. Motor it probably has 80k miles on it, (this is the previous owner guessing)but I will say it does not burn a drop of oil, it doesn't even puff oil out initially after the car has sat for a month. I thought compression would be low and one cyl. really shot so was surprised to see they all were good and fairly close to each other. There are no weird noises or problems nothing leaks (except the standard chev. rear main/ to tranny leak) I would trust the car on a 100 mile trip without a 2nd thought.

    I agree it should easily burn the tires with long tube headers, open exhaust, and a open diff & 3.42 I have a kia optima it prob has 200 hp and I think it would spank it haha that is how bad things are. So something is really wrong with the combo and setup but it is not sticking out like a sore thumb or easily found without tearing into the engine I guess. The timing, that has been checked and re-set. This helped with cranking especially when hot, but not a ton on power. It has a accel distrib, there is no misfiring, also has fairly new spark plugs and wires. They have a good looking burn pattern on them. Where do i look for a #to see which exact heads it has? That is what I can check I agree before putting any money into porting them.

    I thought about a lunati voodoo 268 or something, the converter I thought about using was a PTC so a good converter, not a cheap sloppy TCI or B&M etc. I need to still be able to cruise around, if I want, and keep power brakes, and keep it away from being super high strung in case the gf wants to drive it. I am not going to dump some double pumper carb and 280 cam on it (if it was a much lighter car with a stick shift I might). Right now the headers are warped at the flange and leaking at the heads, (was this way when I bought it) I bought new ones it might help a bit but I don't see it doing wonders.

    A warranty does count for something, how much warranty do the gm engines come with? I would sort of kick myself if I saved up that much $$ and got only a 290 horse motor? This is a good motor, so it is tempting to throw some money at it, but by the time I put in all new high comp pistons, decent heads, cam, and other misc junk I know I would easily be at 1k or greater. Really I wish the motor were just pure junk, and knocking or rattling or something it would make the choice much easier but it isn't. It always cranks right up and runs (slowly) haha.

    Money is def. a object, because crate motors have gone way up in price I see since the last time I checked... it will be a long time before I had 3 or 4k to throw at the car but I don't mind going that route. In the meantime it sucks for it to just sit and not get run. At the same time, I can't see the sense in driving something that gets 10mpg and runs like a dog. My 67 mustang with a straight six is more fun and burns less gas.
    Last edited: Jan 31, 2018

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