[racerboy]

I know the adage, ‘if it broke, don’t fix it’ but I’ll ask anyway. The’70 TA I bought over the summer was basically a .030 stock rebuild back in 2010. Engine only has about 4000 miles on it since then, and it runs fine. I was looking over all the paperwork from the rebuild and it looks like they went with a Melling MTP-1 cam. That can has the following specs:
Duration: 278/288 (204/214 @ .050)
Lift: .421/.443
LSA: 112

I happen to have a brand new (still in the box) Crower 60918 cam, springs and Johnson lifters. I was going to swap out the 068 can in my Judge with this one, but then I sold the car (to buy the TA). The specs on the Crower are:
Duration: 288/298 (214/224 @ .050)
Lift: .444/.467
LC: 112

The rest of the engine is stock RA 3 (carb, intake, rockers, exh. manifolds, points dist.). Car is a 4-spd. with 3.55 gears.

Would this cam swap be worth the effort? Would there be a noticeable performance improvement? Or do I just leave things well enough and sell the kit (I’d probably keep the lifters since it’s always good to have. Set on hand).

Thanks


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[PDC]

That crower is a nice step up in every direction - seat timing / duration at .050 / lift. It sure seems like that much displacement and compression would make good use of the step up cam. I guess the next question is this: when dealing with the cost of a FT cam, the real ‘cost’ is the time and labor to do the swap, whether you are turning the bolts yourself or paying someone to do it. The cost of a FT cam - even nitrided or coated - is not the maker-breaker of that deal. If you are going to absorb the cost of the labor, fluids and gaskets, is there a completely different cam that you’d rather have than the Crower that’s on the shelf?

[scott70]

If your time means nothing and you're not looking for the best cam for the combo deal I'd say put it in. It's not big hp gains but I'd bet you'd be able to feel the difference.

[racerboy]

Thanks for the feedback. I would be doing the cam swap myself and was really only thinking about it since the package is just sitting on my shelf. I’d be curious on feedback on a better cam if I was going to go through the trouble to do the swap anyway.

And just to put it out there, I’m guessing Simone is likely to suggest a hydraulic roller cam. Just out of curiosity, is that a straight swap or do you have to install restrictors like a solid cam? The 400 HO in my ‘67 that I just got back from Barr’s Restoration has an HRC in it, and it feels much stronger than the TA, but I had that engine built by a local shop, so I wasn’t directly involved in the cam installation.


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[tom s]

HRC does not use restriction.You or should I say ifme would use new springs for sure.No matter what you will be in at least $1000 to do the hyd roller cam and lifters.Tom

[NeighborsComplaint]

Probably pick up 20HP that you will feel in the seat of your pants. It will add a bit of attitude to the idle also. Low cost upgrade and probably worth it since it's going to just cost you a set of lifters and, gaskets and some break-in lube. At 4,000 miles your timing set should be just fine and the lift isn't going to be a problem for your current springs. At this performance level, you're really splitting hairs between similar profile cams from the various cam companies.

[steve25]

I would only swap in that other cam once you confirm the installed height that you have on the Exh valves which is 1.560" to 1.60" due to production tolerances.

With stock springs and .467" Exh lift you are really close to coil bind on those springs, so in the least it would be time for new duel springs ( no springs with a flat wire damper in them please!) and your retainer to guide clearance with no guide seal should be ok and will except.500" or a tad more.

If your heads have had a valve job then can likely add .020" to the dimensions posted here.

Also note that if your open spring pressure goes above 270 lbs then it's time for stronger push Rods also.

[taalltheway]

Depends on how you drive the car….with a stick and relatively short gearing this should definetely be an improvement but still on the driveable side of things. I had a Comp cam with 218/224 in my 78 Trans am with a stick and 3.42 gears….it was great.

[Gator67]

I've come to appreciate an engine that runs fine, especially if there are no leaks, so I'd just wait until I were making other upgrades, or something else needed to be fixed.

[OCMDGTO]

Sounds like a lot of work for a small power increase. I wouldn't change it unless it would be a much bigger difference(bigger cam than that) and nothing wrong with HFT.

[Lee]

20hp gain, comparing peak to peak, but LESS power below 4000rpm.


This is just an approximation, predicting flywheel HP/TQ, assuming R/A manifolds and a good exhaust system.


Some changes (like improving the exhaust system, or better flowing heads) will increase the ENTIRE power band. But, changes like camshafts USUALLY primarily shift the torque curve around, which is basically trading lower-end power for more upper-end power.

[NeighborsComplaint]

Cam has less duration than an 068 and has 112LC. It won't hurt the bottom end torque at all and will make more hp and torque all the way across the board than the smaller cam in a high compression 400. The 3.55 gears will keep RPMs in the sweet spot.

[racerboy]

Hi everyone. Coming back to revise this topic only becasieu I just saw on the Buter page that they make a retrofit '068' hydraulic roller cam now. Just out of curiosity, would that offer any performance increase or would you do that just to take advantage of the roller set-up and not have to worry about adequate zinc. Can you tell that I am bored with this 'working from home' stuff and am just itching to do something. I was even eyeing the 428 sitting under the bench and wondering...hmmm...

[tom s]

IMO drive it UNTIL you have to open it up.A hyd roller cam and kit is going to be around $1000.The choice for bigger better cams in both roller and FT is never ending.Tom

[Navy Horn 16]

Originally Posted by racerboy

Just out of curiosity, would that offer any performance increase or would you do that just to take advantage of the roller set-up and not have to worry about adequate zinc.

I run one of their custom HYD roller cams. The best oil to make the lifters quiet is AMSOIL Z-Rod. I tried virtually every other oil (conventional and synthetic) trying to make the lifters quiet down. I don't know if it's the zinc or something else in their additive package, but it works.

You probably know this, but it's more than just the cam and lifters to change to those roller cams. Push-rods and (almost certainly) springs also have to be changed. I thought I was going to into my 1st roller swap for about a grand. Next thing I knew, I was hiding receipts from the wife.

[1968GTO421]

Originally Posted by Navy Horn 16

I run one of their custom HYD roller cams. The best oil to make the lifters quiet is AMSOIL Z-Rod. I tried virtually every other oil (conventional and synthetic) trying to make the lifters quiet down. I don't know if it's the zinc or something else in their additive package, but it works.

You probably know this, but it's more than just the cam and lifters to change to those roller cams. Push-rods and (almost certainly) springs also have to be changed. I thought I was going to into my 1st roller swap for about a grand. Next thing I knew, I was hiding receipts from the wife.

Thanks for this, Navy. I thought I was the only one having to do that