[elimin8r]

I have done lots of research on previous posts about this and most of them date back to 2005. And maybe today it's not worth doing this anymore with all the new kinds of aftermarket heads out there but i have a set of 69 351 heads with the thermactor bump removed.
My 68 289 2V motor is just about dead now so i will get the short block rebuilt soon. To save on some money i want to use the 351 heads. (my 289 heads are probably going to be toast) I have to say that for a stock 289 this motor is impressive. So to get to my question. What Comp cam should i use 252H or 268H or you pick a cam for me?
Keep in mind i like the power of this motor ,87 octane ,MPG and drive it anywhere i want thing, But i do want a little more as long as i am going to rebuild.
Car has a 600 CFM 4 barrel,3.55 rear end ,automatic with shift kit. May get headers depending on cam choice.

 

[mopardon]

With an Auto Trans keep the duration and overlap short unless your going to use a higher stall converter. As for Lift you just have to worry about piston clearance and ramp rates. Have you talked to the tech guys at comp cams? They most likely will know the most about how well their cam perform.

 

[Royce Peterson]

You need to remember a 289 is a tiny motor. Anything you do that reduces torque will make the car less fun to drive. Usually you will lose lots of torque going to the 351 heads because the combustion chamber size is so large your compression drops into the 8:1 range. The exception would be if you used a higher compression piston to make up for the bigger combustion chamber. Your best bet is to rebuild the stock 289 heads with slightly larger stainless steel valves. 1.94 / 1.60 valves are perfect for a 289.

I recommend you try the Comp Cams 260H cam and get a TCI Saturday Night Special converter. Rebuild the stock heads, or buy a set of aftermarket aluminum heads that have 60 CC combustion chambers.

 

[elimin8r]

Have not talked to comp cams tech guys. So many choices. Because i am not going for big HP gains i thought this would be easy. Best i can tell stock lift was only 368 in. and 381 ex. could not find anything about stock duration. I would think with a little larger valves and no thermactor bump i would benefit with a cam that has more lift.

 

[elimin8r]

Royce am i wrong that the 68 289 C8OE heads are 63cc and the 69 351 C9OE are 60.4 cc ?

 

[Todd]

Measure,calculate,measure,calculate,and measure again. Get the heads measured if I didnt mention it. Dont go by what the average cc was suppose to be 40 yrs ago.
The 351 heads will give a little more more power as is IF you measure the chambers and get the correct pistons to get the compression where it needs to be based on the cam and fuel and the rest of the combo.

 

[Royce Peterson]

The '69 351-4V heads are around 80 CC. You can probably find a chart on the internet somewhere that says NHRA minimum is 60CC, which is a rule, but you have to mill them .100" to get there. The stock 289 heads are about 65CC.

I did exactly this swap back in 1978. The 351 heads absolutely killed performance. I milled the '69 351-4V castings .050" and installed 2.02 / 1.66" valves. The car had an Edelbrock Torker 289 intake, Cyclone headers, Corvair Turbo mufflers, Accel dual point distributor with a Mallory Voltmaster coil, and a Holley 600CFM carb. Cam was a Crane Blazer 272. Swapping back to stock 289 60CC heads made the car a lot more fun to drive.

This car ran 16.00 in the quarter mile completely stock with the "A" code engine, 4 speed, and 3.20:1 gears. With the modifications and the 289 heads it ran 14.50 at Green Valley raceway in Hurst, Texas.

 

[dsmag68sb]

Happy New Year to everyone, what are the spec's on the cam ? (lift, duration, etc).

I had 1970 (DOE) 351W 4V castings on my 68 302, I thought they had 60.4 cc volume, added 1.94/1.60 Chevy valves, home porting job, with dome pistons I had 10.7:1 compression (calculated), I used a Crane solid cam with .552 intake, .573 exhaust, 244 deg duration intake (at .050 lift) and 252 deg duration exhaust, lobe centerline was 108 I think. Best time I ran was 12.37 at 109 mph in the quarter, best 60 ft was 1.72 (I think - recalling from memory), had a tunnel ram with two 450 cfm holleys, long tube Hooker headers, 4000 RPM stall (flash) with 4.62 gears. I drove this on the street although the stall converter was the biggest impediment (lots of slippage - lots of heat), hit 3000 RPM at 50 mph as I recall, a bit slow on the double lane highway.

 

[elimin8r]

80cc's ? Is that like total combustion not just the cyl. head chamber size? I see some 351 pistons have 17cc dish to them and 289's have 5cc flat top valve relief.
I used a compression calc. and these #'s .
60.4 cc chambers
4.030 bore
2.87 stroke
5cc piston dish
.040 gasket thickness
.015 deck clearence..... But i do not know this number untill i measure it (anyone know stock 289 clearence)
Came out to 8.85 to 1 Wanted 9.2 to 1.
These heads were on my stock 69 cougar and ran 14.3 1/4 mile 97 mph at best run so i know they are in decent shape and thought i would use them if i can.