Thinking about a camshaft upgrade

[PierreBelvedere]

So, I´m really disappointed in the low end power on my 273.
Can´t get it to break traction even on rainy days!

Here´s my current recipe:

273 Standard block, bored over 030.
Flat head pistons.
Weight adjusted pistons and connecting rods.
340 camshaft with hydralic lifters.
340 Valvesprings.
Home-ported heads (matchported and cleaned up channels)
Heads machined by 0,5 millimeters.
Running with the thin head gaskets.
4bbl intake, cast iron.
Edelbrock 600 carb.

3,23 rear end and 904 tranny.
The car is a -65 Belvedere.

Thinking about choosing another camshaft, with more low end power.
Do you guys and gals have any recommendation?
Rough idle, smooth idle, does´nt matter.

And yeah, I know that there´s no substitute for cubic inches.
But what the hell, I like my little power plant.
Just want that little extra low end torque, so that I can break traction.

 

[Sonny Black]

also, 391 rear... should do it!

 

[wedgie]

You're way overcammed. That cam would be too much for a street driven 318 and is even worse in a street driven 273. When I first bought my '65 Coronet, it was powered by a 273 with an adapter plate to mate the 600 Edelbrock carb to the factory 2bbl intake. Had the stock pistons, but an RV cam (Elgin). The thing was actually surprising for what it was.

 

[m79ded]

Try the voodoo 60401 cam I have heard alot of good things about it.Seems right on the money for the small motor. Makes lots of vacuum great response. That should wake it up.
But the old saying goes no substitute for cubic inches.

 

[Cranky]

No one is asking where the cam is set at. Was it installed with a degree wheel or was it just installed using the 'align the dots' method ? I've seen cams as much as 8 degrees off when done that way and if it's 8 degrees retarded, then that might be your problem. Imo, that cam isn't too big. I have run bigger cams in 318's that ran hard. Does it have a rough idle and does the engine run pretty good above 3000 rpm? If so, I'm betting your cam timing is off....

 

[Meep-Meep]

Are you running the later 340 cam? Or the 68 manual trans cam, which is the hotter of the two. Do a cranking compression check. The 273 with the smaller bore may not build the compression like you think even after milling the heads. What heads are you running? If 360 heads you may be in trouble. You should be in the 150 PSI range or better to have something respond decently with a mild cam. What about distributor curve and basic timing? Go through all the basics before you dig into the cam swap.

 

[69 roadrunner]

on the cam subject I just degreed my cam on a 440 roadrunner becouse the low end suck I lined up dot to dot when installed. ran the car runs good but still no low end after degring cam its 8 btdc should blow tires of but dead. still looking the motor is fresh. 30over small chamber heads big valves 750 double pumper auto trans 391 gears 93/4 to 1. very frustrated.

 

[robinsonwr]

No one is asking where the cam is set at. Was it installed with a degree wheel or was it just installed using the 'align the dots' method ? I've seen cams as much as 8 degrees off when done that way and if it's 8 degrees retarded, then that might be your problem. Imo, that cam isn't too big. I have run bigger cams in 318's that ran hard. Does it have a rough idle and does the engine run pretty good above 3000 rpm? If so, I'm betting your cam timing is off....

I am with Cranky on this one. More information would be nice too.

 

[69 roadrunner]

Iam running 224/234 at 50 and 465/488

 

[wedgie]

When you change a camshaft to a higher output type, you normally lose cranking compression. Always kills or at least hurts bottom end performance, how much depends on how "wild" the new cam is. If you are happy with your higher RPM performance in comparison wit the previous camshaft, you may want to compensate by going to a higher stall convertor and a lower (higher number) rear end ratio. Degreeing any camshaft should just be part of any good assembly practice.