I agree, small block chevy is the way to go... anything bigger will twist your unibody with all that torque. I've heard of Vega's with their doors welded shut b/c of that. Keep it simple friend...besides, a big block is much heavier than a small block, that increases your weight without adding that much more power... see if you can find a 400 small block if you need that big number on your fender.
As a former owner of a V-8 305 Monza, I can attest that the extra torque of a big block would be much more than the uni-body could stand, since I personally had to pull the small block out to get the uni-body re-welded. But if you must increase horsepower, I agree with another's comment about looking for a small block 400. But you would probably still want to look towards a frame connector application to stiffen things up.
I would like to own another one of these great little cars, as I ordered mine from the factory in 1979, and was only able to enjoy it for about 4 years until life happened. I can still remember picking it up from the dealership, looking on the odometer and seeing that .2 miles on it; I can only guess this came from driving the car from the assembly line to the delivery truck.
I am now almost 48 years old, but still think of some of the fun I had in this great American built car from Chevrolet.
I have a 77 Spider 2+2. Awesome car!
When my clutch got stiff, I found that the fire wall was trying to tear out around the cable mounting. Straightened it out and reinforced it, and now it's smooth as silk.
I have a 1979 Monza that originally had the 305 in it. I love the car and wouldn't trade it for anything else. It handles like a go kart and since I put the 375 HP 350 in it, it goes like stink. I now race it at the drag strip. Monzas and Vegas had to be the best cars to buy for playing with and hot rodding.
Me and my dad just bought a 1978 Chevrolet Monza Spyder 2+2 hatchback that originally came out with a 305, but now has 4.3 V6.
The car has a lot of power and is very fast.
It probably one of the prettiest cars I've seen.
The car has the typical rust on the lower quarter panels and floor pans. We hope to have it fixed by next year.
We're going to have it painted orange with a black spider stripe.
I just bought a 1978 chevy Monza spyder 2+2. Just recently had it painted candy apple red. Have done several repairs to it, runs great. It has a 4.3 V6 has great power, had considered selling it but haven't decided, can't get over the power this car has. I think it's an awesome car..
Hey guys, I own a 1979 Monza Spyder with a small block 350 with Vortec heads, Edelbrock intake, cam and carb. This car ran over 300hp on a dyno earlier this summer, but I can't remember an exact number, If you run high hp setups you must reinforce... I have bent the hood and caused my beautiful Ferrari Red paint job to crack in three places. This car is amazing... It is the fastest street car I have ever driven that isn't modernized. It came with 2:53 rear end gears in it, and I need to get different gears, I am looking at 3:23's. This car will scream after this...
I have had a 1979 Monza with the 305 in it for about five years. I got it for $1100, and put about $2300 in it. Also it only had 60,000 miles on it, so I think I got the better end of the deal. I love this car, and can't sell it. Chevy all the way.
Late to this site: I bought a 262 V-8 Monza 2+2 in 1975, and within two years I stuffed a 331 375 horse SBC into it. I replaced the clutch with an 11-inch (I think) unit, and thereafter had clutch cable breakage. I purchased a 2.93 "limited slip" rear end from a wrecking yard, had the axles drilled for 5-lug Chevy wheels. I ran 14x7 Centerlines with 50 series rear tires to keep the ratio decent. Never had body flex problems, probably because the tires were lit up all through first and most of second gear. Ran mid-12's at Redding drag strip back in the 70's.