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cam for a 350 truck engine?

2K views 26 replies 8 participants last post by  454C10 
#1 ·
My buddy is installing 350 crate motor in his 4 door 49 ford.
I just bought a 49 4 door chev, W/ 1975 2bl. 350 truck engine.
The plan is to run em out at the strip.
My heads are 74.5 cc and 1.72 intake- it's going to be a wheezer.
He's heard it run and knows it's stock.
I'm thinking of slipping , say a 210* cam in with out telling him. Leaving the two barrel on till i can afford heads and 4 barrel.
Any suggestions on the cam?
thanks Pat
 
#2 ·
Look at different cam characteristics from the manufacturers. Basically, a wide LSA, limited lift and not much overlap if you want it to sound stock. You can also advance/retard the cam position to move the powerband up and down. When deciding on a cam, keep in mind how much fuel flow you have to offer.

Hang in there, some of the cam guru's will chime in.
 
#3 ·
It's gonna be hard to see any improvement from a cam swap if your fuel & exhaust won't support it.You could actually make it perform worse.What heads do you have that would have a 1.72" intake valve?You would get better results by swapping rear gears out than the cam & they would still be there to use when you get around to making more improvements.
 
#4 ·
It's gonna be hard to see any improvement from a cam swap if your fuel & exhaust won't support it.You could actually make it perform worse.What heads do you have that would have a 1.72" intake valve?/QUOTE]
The numbers I got off the heads 3998991, 74.5 cc chambers.
Don't think I'm going to do anything right now, found out he bought the cheapest long block he could- 76 cc chambers. Although he'll have a 4 barrel, I think his 4 door 49 is heavier.
I've got the stock headers but short glass packs, they should breathe alright.
I'm going to put that money on a shifter kit for the TB350.
You may be right about the gears, the kid at the trany shop says it's low geared.
Thanks Pat
 
#5 ·
Is your engine a 283 or 307?Its good to know what you are starting with. IE;a 283 is 200 hp in stock form.A well built 283 with all good parts can make 300 plus HP.
Most bolt on performance parts are designed to improve power on 350 cubic inch engines,(perhaps not ideal for a 283).Adding a cam to a small engine and not having manifold,carb and headers might not give that much more power.
 
#6 ·
sorry,I see you have a 350,,,
do you know the CR?A cam swap is usually the item you pick after you buy heads .If the engine will be very close to stock all of its life I would get a short duration roller with .480 lift. The lobe separation and displacement angle to be determined after you know the CR.I would buy a good carb and manifold because the engine is coming apart for the cam swap. Headers are the most important item.Small tube,1 5/8 inch primaries.
 
#13 ·
Install an Edelbrock Performer cam. Good for a stock engine. 204/214 duration (I think). Summit racing makes a copy for cheaper ($100.00 with lifters).

This cam plus headers and a 4bbl should get around 275hp in a 350.

The cam should help even with the stock manifolds and 2 bbl.
 
#15 ·
110235-12 CL110235-12 266 270 213 217 .485 .495 112 108 Hyd. Hyd. 1,2
1000-5000 Good idle, Off-Road & Street Performance. 9.0:1 CR advised.

start here as a place to do some math,,,
expensive investment if no support equipment is installed to match performance possibilities
 
#16 ·
above cam is 108º intake center line
112º lobe separation angle

perhaps you might like similar specs but with the intake center line down around 102-104º?
you need to know CR for fine tuning and the type of power delivery you prefer

some of the hotter street LS engines are going the other way, 112-116º lobe separation angles like you would if you were building a bbc. also a smaller cam can give a wider power band with slightly less punch,,,
all has to do with when the intake valve closes and valve timing overlap
 
#17 ·
Thanks for the help guys, I've got a performer cam coming.
This is supposed to be a sleeper, i want to keep the stock exhaust manifolds and two BL. My buddy's seen it and heard it run, He's got a 49 ford 4 door W/new sbc 350 crate motor and small heads and cam. And wants to run em at the track.
I might need some help jetting the carb if it runs lean though.
Pat
 
#18 ·
The best bang for the buck upgrade wont be to the engine in fact you'll see better results by changing the rear gears as joker suggested


If it were me and I needed to do one simple upgrade it would either be a converter change or a rear gear swap.

The stock camshafts were intended for good vacuum and idle characteristics.

Change the Rear ring and pinion gear to a 4.10 ratio or a 4.30 and you'll smoke him no doubt about it.

Its easy to see what gear you have now here is an example.

tire spins 10 times and driveshaft spins 37.3 times its a 3.73 rear gear if the driveshaft spins 41 times its a 4.10 rear gear I usually only spin it one time and see how many times the drive shafts spins and go from there.

be aware of an open diff

the amount of times the driveshaft spins in relation to the rotation of the rear tire/tires
If it's an open diff: you have to make 2 full revolutions and count the amount of times the driveshaft spins.

for a LSD (posi) its 1 full tire revolution in relation to the amount of turns on the driveshaft.
 
#21 ·
That 'd cool if I had a tac.
But now I'm not even sure what engine i have.
A 350 starter wouldn't match up. I suspect it's a 305 el camino/chevell engine.
Thanks for the tip on spinning the tire, I'll check that also.
It's supposed to be a 57 chev rear--but my 350 vette engine has morffed into a 350 truck and again into a 305
whatever.:pain:
Pat
 
#20 ·
DO NOT buy 4.3 gears for a stock engine! Yes it would accellerate off the line better,thats all.It would destroy your mileage unless you also installed an over drive transmission.Buy a 50 horse power nitrous kit and hide everything.
The 2 BBl carb wont make much more power with a better cam. The cam is to improve breathing. The biggest breathing improvement for the least money is "exhaust" start there
 
#23 ·
Joker I'm getting real confused now
the block # 3970010-- I'm told the 10 is 4 inch bore
the the head numbers 3998991 and c18A and M3
gave me a 74.5 cc chamber W/ 1.72 int. 1,50 exh.
The stamped # VOT30TXD I didn't have too much luck with.
I was told for sure this was a 75 truck standard cab.
:confused:
 
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