OK so I am getting ready to drop my 350 off at the machine shop. I am going to be shopping for my bottom end while it's being cleaned and magnafluxed. I am not going for a 500HP performance rebuild here. Basically I am doing a 350 4 bolt main, bored .030 over, Comp Cams XE 262 cam, Vortec heads, Edelbrock Performer RPM intake, headers, a 2-1/4" dual flowmaster system, and a Holley 750 vacuum secondary carb. My car has a turbo 350 and by the time the motor is finished, it will have a 2200 RPM stall converter, a nice shift kit, and a 12 bolt posi with 3:31's. As you can see I am not going to be racing this car. What I am looking for is a 350 HP street motor.

My main concern is this...when shopping for pistons, can I get 350 HP out of this motor with a dished piston?? I know that the Vortec's have 64 CC combustion chambers. If I run a flat top piston I am figuring that I will have around 9.75 to 10-1 compression. If I run a small dish I figure I can drop my compression to maybe 8.5-1 or 9-1. My basic use for the car is a weekend cruiser. I highly doubt that the car will ever see the track (maybe once a year to get timed), and I DO NOT street race. My car is all original with only 88,000 miles on it and I don't want to start hacking it up, all the changes I am planning on making can easily be reversed. I just want to pull the original 307 and drop in a motor with some more power. So my main question is can I get 350 HP with my cam, the Vortec heads, and a dished piston??

Although I'm no expert on engine combos, I think you're right on with your 350hp estimation, I bet it will make around 400lbs of torque---nice cruizer for sure. graemlins/beers.gif

I'd go with the flat tops for a weekend cruise, your aim shouldnt be mileage, and it'll help towards your 350hp+ goal:) Also dont forget to grab some new motor mounts for the 350:)

Originally posted by 68Nomad:
I'd go with the flat tops for a weekend cruise, your aim shouldnt be mileage, and it'll help towards your 350hp+ goal:) Also dont forget to grab some new motor mounts for the 350:) I wasn't so much concerned with mileage as I was with 10-1 compression. Yeah I will definitely do the new motor mounts, I haven't decided whether to change the frame mounts or not.

A 12cc dish, get the reverse domes, will set the static CR at about 9.5. This would be excellent with the 262 cam. DCR about 8.02. BTW, with flat tops and 64cc chamber the SCR is about 10.2 or so, a little tight for the 262 cam .

Nice combo. I have the XE268 cam in my 400 and have been very happy with it. The 262 in a 350 should act similiar to a 268 in a 400. You can hear the cam when it is cold and its almost smooth when warmed up. Chevy high performance built up a motor similiar to yours a couple of years back and it made just shy of 400 hp with the 268XE cam and vortec heads. I was thinking they had about 9.5 compression. I would think the 262 cam in the same 350 would easily make 350 hp. I think your parts are nicely matched and the cam, gear and converter will work well together. I would expect high 13s @ 101-102 mph with traction.

Awesome! That was my concern. I wasn't sure if the 262 was the right cam for 10-1. But I also was concerned with 8.5 or 9.0 for the power I wanted. High 13's would be fine, like I said I am NOT racing this car. I just want a little more "umpfff" than my 307 offers. Plus it kills me to not tinker with something you know??? If I know myself, I will do up the 350 and drive it for a year or 2 and then decide that I need a big block.

I have almost the same combo in my other chevelle except i have the small chambered corvette heads with the flat tops. I dont ping either. Im running the xe262 and like it. It has tons of low end and midrange but very weak up top. Im also running my stock converter as recommended by comp cam. I have 3:55's in my car and like it.