How can I get more power from a 428CJ?

[cobred]

You should also check what mufflers are inside your sidepipes. When I first built my car I bought the sidepipes from ERA and didnt ask anything about mufflers. The ones they gave me had 2" mufflers inside the pipes. A few months later I bought a used set with 2 1/4" mufflers from ERA then a year later I sent the first set to the exhaust shop ERA uses and had 3" mufflers installed.
Each change made a difference but I made other changes at the same time so its hard to say how much of an increase but what goes in must come out.

[olddog]

Originally Posted by cobred

You should also check what mufflers are inside your sidepipes. When I first built my car I bought the sidepipes from ERA and didnt ask anything about mufflers. The ones they gave me had 2" mufflers inside the pipes. A few months later I bought a used set with 2 1/4" mufflers from ERA then a year later I sent the first set to the exhaust shop ERA uses and had 3" mufflers installed.
Each change made a difference but I made other changes at the same time so its hard to say how much of an increase but what goes in must come out.

Good thought and while your at it, make certain your air filter is not choking off air flow. Air flow into and out of the engine is king.

[ERA Chas]

Nothing suggested here will give the meaningful improvement in power you seek except a cam change accompanied by head improvement or change and carburetor improvement, as Brent suggested. The other ideas are fine to augment those basic changes.
Those changes will alter the docile performance you now enjoy so be certain what your desires are.
Start by going for rides in cars with several levels more power than you currently have. Then decide what you want to live with. I have in mind a certain blue/white car with magnesium wheels as the upper end of the scale for power in proximity to you.
The actual parts and procedures are easy to ID and source from the forum then.

[PurpleVenom]

My path to 50 rwhp gain and 40rwtq as follows:
- Changed to higher flow air cleaner/filter - K&N - yes, this was 10 hp and 10rwtq per the dyno
- Port matched my intake to my heads (460 - Torker 2 intake - Cobra Jet heads) - this was 40hp and 40rwtq per the dyno

I realize my engine is a little different and the intake/heads aren't quite the same, but check this first. The above cost me $250 + dyno time. Timing set to 18 initial and 38 total (mechanical advance)

Good luck!

Tim

[ERA Chas]

460's with CJ heads breathe 100% better than low-riser 428 heads the OP has. That's why those minor improvements produce such results. Not a helpful comparison.

[Lexcob]

Jam a couple of turbos on the old girl!! That'll liven things up a bit!!!

[RICK LAKE]

ERA427 You have the same problem as other guys with cobras and running a 400hp/450torkmotor. You are trying to push a barn door through the air. If you want to stay with this motor and give the car some more pickup,here are the 2 things to change, Mufflers and gears. Mufflers have been covered here with the internal size of the inlets and outlets. You will pick 20-28HP in top end if you go from 2" centers to 2 1/2". You also will need ear protection with the louder exhaust. You have an overdrive 5 speed trans. What is the rear end gearing? We need to go up in numbers from say a 3.07 to either a 3.31 or 3.54. This will give you a faster car from "0" to "100".
I have been running 3.31 gears with both motors. I do have 2 different trannies for the tracks. The trick is the keep the motor in the power band all the time between torque and HP. YOu want the motor to cruise in the torque band at about 750 rpms from where it starts and no more than 500 rpms pass where the motor HP maxes out. After this you are just wasteing motor.
You also need to remember the air drag keeps doubling every 10 mph added to the speed of the car.
Suggestions, want more power, build another motor that is aluminum to save weight on the car and a stroker in the 480-527 range. Save this motor (428)for a rainy day or resale. Other ideas are to build a windsor stroker motor. This about 1/3 less in cost and parts are easier to buy and build with. Power limit will be in the 400-800HP and 300- 675 ft of torque ranges.
Last, not sure of your driving ability, but when you start getting to this kind of power numbers, your driving skills better improve to hand this killer. Been there,done this too. The different between 368h and 448 of torque and 540hp and 620 of torque is HUGE. Find out what the gearing is too start. I think you will be happy going up 1 higher number of ratio. You can get a Jag center section and swap over all other parts. Good luck. Rick L.

[PurpleVenom]

ERA Chas - He mentioned he's running a 428 with the stock Cobra Jet heads is the reason I gave my comparison. The 428/429 CJ heads are what's used on the 460. Maybe I misunderstood the original post or yours, but in either case - he needs more air in or out which will produce more power. Not too much air out as this will reduce torque (the go that get's you there faster). Anyway, my .02 worth, thought it would help. See ya.

[vector1]

what does your air cleaner and exhaust look like, those are your primary limitations, another would be your cooling system.

[ERA Chas]

Originally Posted by PurpleVenom

ERA Chas - He mentioned he's running a 428 with the stock Cobra Jet heads is the reason I gave my comparison. The 428/429 CJ heads are what's used on the 460. M.

The 460 you have is a 385 series engine-his is a 428 FE; two completely different engine and head designs. Yours came later and are superior to his. The 'CJ' moniker is Ford marketing BS but used on two different-headed engines.
We both agree-he needs more head flow

[ERA427]

So I'm running a 3.54:1 rear with my TKO 5-speed. I know 5 is an overdrive so I can't expect too much there. I do have a good timing light so I'll make sure the distributor if optimized. I haven't checked my air filter - it's one of this giant ovals with the black and aluminum fluting on top that says "COBRA." I'll see if K&N makes one for those. My pipes are the ones ERA uses from a company called Stainess Specialties. I inquired with ERA about what's inside of them for mufflers. They didn't specify other than saying that it's a very good design and better than what you get if you don't opt for the stainless option on the pipes. However, I think it sounds great but I don't need ear protection. Also, I don't want to need ear protection, and I don't think I want to attract any more attention around town than I already do. So I'd rather focus on other ways boost it up a bit.

Sounds like timing and air filter are two pieces of low hanging fruit.

I believe my PI intake and CJ heads should already have a matched port size since they are both designed for each other (right?). But I suppose you could report them both for a better overall airflow design.

Great input from everyone on this. And although I believe I have a pretty good natural/learned talent for keeping this car stuck to the road, I do plan on taking this to a driving school also. But again, I'm not looking to go over 500hp - "just" high 400s.

Given all these new mustangs, cadilacs, BMWs and yes, even Hyundais coming out with crazy power these days, I really don't want to risk embarrasing myself out there!

[ERA427]

whoops

[DanEC]

I wouldn't assume your heads and intake were port matched. If it's a stock rebuild they probably didn't touch them.

[DanEC]

I wouldn't assume your heads and intake were port matched. If it's a stock rebuild they probably didn't touch them.

You might want to do a compression check and leak down test of your motor before doing too much to it. You should find out if your motor is basically healthy before getting too deep into it. If you have a couple weak cylinders then a lot of these suggestions are going to produce marginal results.

[ERA Chas]

Originally Posted by DanEC

I wouldn't assume your heads and intake were port matched. If it's a stock rebuild they probably didn't touch them.

You might want to do a compression check and leak down test of your motor before doing too much to it. You should find out if your motor is basically healthy before getting too deep into it. If you have a couple weak cylinders then a lot of these suggestions are going to produce marginal results.

Perfect advice.

[undy]

Originally Posted by ERA427

I haven't checked my air filter - it's one of this giant ovals with the black and aluminum fluting on top that says "COBRA." I'll see if K&N makes one for those.

I found the CFM rating for the K&N oval filter to be a bit lacking for a "healthy" FE so I made some changes to mine. I modified the lower lid to set lower and accept a taller filter element ( 2 1/4" vs the 1 7/8" standard one) I also had my local machine shop cut the top lid to install a late model GM K&N filter(3.0L V6). I chassis dyno'd the car before and after the modifications and picked up 14 RWHP from the changes, a significant improvement.

[Dwight]

a lot of good suggests.

I think a basic tune up, the correct timing, correct jetting and correct air cleaner could yield a few hp.

I worked on a 351W last fall that had 2 previous owner with 11,000 miles on the car. The third (new) owner wanted me to do a few maintenance items. I drove the Cobra for 20 miles or so to get the feel of it. Ran good but would not rev above 4300 rpms in any gear. I removed the 8" S&H air cleaner and it would go to 6000. 11,000 miles and no one noticed it would not run above 4300 rpms?????
Changed the carb, corrected the jetting. Picked up a few ponies and then he decided he wanted 500 hp.
Called Keith Craft and ordered a 408 with 530 hp.
We also changed the mufflers to Classic Chamber 3".
I never did see what that Cobra had with the new motor, tires, trannie, etc. but I think it's very fast.
And Mike drives like an old lady. But he very happy with his new Cobra.


My suggestion is that if you want 100 more hp call Keith and see what heads and a cam to match would cost. You will gain the most hp from that.

and DanEC advice is basic to any changes you want to make.

Dwight

[decooney]

+1

If your heads are worked some already and the cam specs are reasonable now, I'd start with port matching, distributor initial-total, A/F ratio carb tune or upgrade next. Should be enough to overpower basic street radial tires. If not, go back and take another look at cam and heads as others have suggested. Otherwise, a good tuner can typically find a little more here and there. Good Luck.

[rpatton3]

The side pipes might a way to free up some horsepower if they are too restrictive.
Do your mufflers pass the tennis ball test?

If not, maybe you need better exhausts!