small block fresh up

[Confusedcuda]

Hey guy's, I have a 67 barracuda that has a 2 bbl. 273. I am going to pull the motor so the engine bay can be painted and while it is out I am going to have it freshened up. It has about 14,000 miles on a .030 over rebuild about 26 years ago. I was thinking about maybe installing some 273 Commando hi-comp 10:1 pistons and maybe putting on some 302 or similar heads or I was just going to stick with stock 2 bbl. pistons and maybe have a little work done to the stock heads (mill,valves,etc.)and in both situations go with just a little bit bigger cam. I am not trying to build a race car but maybe gain about 25 or 35 HP. I allready have a 4 bbl. and hi-po elec. ign. and headers and duals, etc. on the little 273 now and it doesn't run too bad. I guess I am just wondering if the hi-comp. pistons and different heads would be worth maybe the extra 500.00 or so to freshen up. What do you think? I do want to keep the 273 in it #'s, everybody first suggest ditching it but I would like to keep it as original as possible, I know it's weird. THANKS:blah5:

 

[redfastback]

nothing wrong with a 273. keep it original, screw everybody that says otherwise. i would stick with around 9.5:1 pistons, mid 260's cam duration, and be able to have a peppy, just above stock 273. when my 273 in my dart wagon is ready for a rebuild, that is about what i will do. good luck.

 

[RedFish]

If you dont already have the 10 to 1 dome top pistons for the .030 over bore you can spend 600 bucks right there. Best advise I can give is forget headers.
Dakota exhaust manifolds and duals will give you better flow than the stock manifolds and a little more hp. I'd poke a new oil pump in it while its out and drop electronic ignition in it also. Tune and tweak to as good as 273 /2brl gets and let it be.
I'm sticking with stock 273 also. If I wanted a rubber burning ,neck snaping, hotrod I'd replace everything from the radiater cap down and back to the rear end. That is pennywise and dollar foolish in my opinion.

 

[rumblefish360]

To pick up power with your engine while keeping it cheap, I would have the valves and seat area's well preped. If your looking at a cam change, I'd look at more lift while keeping the duration the same or at best just a few degrees more.
A split duration cam would work best in helping the exhaust exit. And while I'm on exhaust exiting, if you have true duals, I'd spend the money on a X pipe system. You'll pick up alot of power this way while keeping in the same power band your in now.

 

[moper]

I dont know when the intake angles changed.. Was that 66 or 67? I would replace the heads with 302s and keep it simple. I dont think you'll hurt anything, and a stck done set of 302s will work better on a 273 than the original 273 heads will. I agree with not worrying abou headers... If you want to spend a little, my '66 Formula S used the 68-71 hi po 340 manifolds and they fit fine.

 

['64 Cuda]

66 was the first year for the new intake manifold bolt angle.

 

[65 Dartman]

If you want to spend a little, my '66 Formula S used the 68-71 hi po 340 manifolds and they fit fine.

When you used those manifolds, how hard was it to fit the exhaust pipe to the driver's side manifold in the 66 since the 340 manifold is shaped quite a bit different in that particular area as compared to the stock 64-66 manifold?

 

[perfacar]

hi, the 2bbl 273 has 8.8 cr ,by cutting the deck, and the heads, can achieve 9.5 cr. the 273 heads will outflow the 302 heads in the .100 to .450 lift range.
the 273 head has a fatter flow curve. there is about 37 CFM more flow at .300 lift in the 273 head.at .500 lift, very close same. the mid lift flow curve is where the valve spends most of its time,opening and closing. the 302 head has about same shape combustion chamber as the 273 . If you want better flow, just install good sst valves. the 273 head responds very well to that change. the 302 didn't!!! i have tested both heads on a flow bench.

 

['64 Cuda]

When you used those manifolds, how hard was it to fit the exhaust pipe to the driver's side manifold in the 66 since the 340 manifold is shaped quite a bit different in that particular area as compared to the stock 64-66 manifold?

I'm curious about this too. I've been told they'll fit with a bit of grinding, I've been told they won't fit, & I've been told they'll fit but you can only get 2 1/4" pipe to fit through all of the linkage.

 

[66dartgt]

Cam change to something similar to the stock 340 cam would be nice - bowl port the heads and port match them, hard seats (at least) on the exh. replace/inspect the timing chain, and oil pump, inspect/replace the bearings. If the motor was running well, I'd leave the rings in it that were already there.

 

[jaxle]

if you change your cam up consider the right converter as well.