Engine Cam

[Nosub4cid1966]

Alright, I bought an engine from an '88 mustang. Complete stock bottom end and GT40 heads (3 bar and 1.54" exhaust valves, 65cc chambers). The motor received an alphabet cam (e) with the heads. The motor is going into a classic mustang with a 5 speed swap...

1) is worth a cam swap with the technological advances in past 20 years?

2) I called comp cams and they couldn't tell me what I would have to do (ie machinine work to heads) in order to run a thumper cam. They told me not to run extreme energy and said that I should run a 35-440-8 cam...but again couldn't tell me if it had too much lift for GT40 heads...anyone running this cam? What had to be done?

Anyways, I don't want to have to take the heads off to have them machined because I might as well get AFR 165'S if I go down that rabbit hole.

 

[General karthief]

What is your goal with the car and what other mods are you planning?
Carb?
Gears?
Wheelies?

 

[Nosub4cid1966]

Currently motor is going carb because its going in a classic mustang. Might try Fitech down the road. Keeping the t5 that was attached to it. Car has 9" with 3.00 gears, might eventually go 3.55/3.73 with the 5 speed having OD. Looking to get max street performance out of those smallish heads. No intention of racing, just best seat of pace acceleration.

 

[General karthief]

What kind of car and what does it weight?

 

[Nosub4cid1966]

1966 mustang coupe...about 3000# with driver

 

[Nosub4cid1966]

1966 mustang coupe...about 3000# with driver

 

[General karthief]

E cam will be ok I think, take a peek inside the spark plug hole a make sure the pistons have the eyebrows, I don't know about the thumper cam lift specs, I know they are not efi friendly, too much overlap, that might be why the rep popo't it thinking you are efi.

 

[Nosub4cid1966]

pistons look identical to the ones in this motor, has valve reliefs and what looks like a recessed looking area in middle...

Thumper cams come with 3 variations in lift here are specs (cams listed most radical to least)
.552/.537 243°/257° @ .050 rpm 2500-6200
.540/.526 235°/249° @ .050 rpm 2200-5900
.531/.515 227°/241° @ .050 rpm 1900-5600

How much lift is too much for GT40 heads, I hear the "P" heads can't take that much without machine work.

 

[General karthief]

Don't over think it, it's a street car and you want it to be fun to drive
373s can be fun 355s are a compromise, look for torque, I believe those heads are good for torque to get you rolling, your likely not going to spin it over 6k maybe the smaller cam will work good just don't go with the big tube headers, long tubes for good low rpm torque, it won't need a big carb, duel plane intake
My gt40p heads had a max lift around 600 but they where new and machine shop prepped

 

[a91what]

With a t5 and 300 gear you will want as much torque as possible. The e303 has a range from 2500 to 5500.... it does make torque but is so out dated....

There are plenty of cams that work with gt40 heads.
-E303 is 220duration and .498 lift.. with a 1.6rr
This cam with 1.7rr on my engine was nowhere near the pistons when I tested p2v

I would look for a split duration cam like a trick flow.

 

[Nosub4cid1966]

Yeah I forgot to add the car does have tri-y headers and 2.25" exhaust...plan on moving up to 2.5" with h pipe down the road. Carburetor is 4160 600 cfm. Current intake is an edelbrock performer. Didn't realize the e cam power didn't come in till higher RPM. So the intake is probably not a good match for e cam...

So my thoughts right now are the smaller of the 3 thumper cams and maybe a performer RPM intake.

I just wanted to make sure I wasn't wasting too much $$$ and parts would fit with what I plan on running.

 

[General karthief]

Going with what 91 said, I would move the rear gear up to maybe a 350, talk to the cam people and tell them your specs and your intended upgrades,
Sounds like it's gonna be a fun ride.

 

[Nosub4cid1966]

I know something has to be done with the motor...I put it in the car already with the c4 auto that was already in it (due to lack of funds for all the nessesary 5 speed swap parts), and the car is a DOG off the line...feels slower than my 4 cylinder S.T.A. until revs go up to about 3k, then the motor screamed and it started to pull and then it rolls over at 5k... Yes I know the stall speed on the converter is too low, but I was so disappointed that I almost pulled the motor. I know I have to get the 5 speed in, rear gears are in the works, but the open different has got to go too and that's just not in the budget...but yes a cam is...

 

[General karthief]

I think the dog needs a gear, kind of a miss matchup of parts.

 

[a91what]

Or a 6-71.