[racerboy]

I had the original WS motor redone in my Judge about 6 yr. ago. I went with good H-beam rods and forged pistons. I don't recall the deck height (I have to dig up some of that paperwork). Stock #12 heads were refreshed and new valves. I went with an OEM (as in, still in the GM canister )068 grind cam. I just re-installed the 7040573 carb that was done by Cliff . I'm not that happy with the performance of the motor, plus the stock hydraulic lifters are making a lot of noise. I was thinking of doing a cam swap this winter, and maybe going the roller-hydraulic route, but had a couple of questions about the cam and also about the heads.

Camshaft/Lifters
What's a good flat-tappet replacement for the 068? I hear a lot about the Crower 60916 (I think that's the number). Car is a manual brake, but I have not ruled out adding power discs up front at some point.

If I went with a hyd-roller, what kind of lift/duration would i select (heads are refreshed, but unported).

Would switching to straight 30W oil quiet down the lifters?

Cylinder heads
I thought I heard some pinging last time I drove it (have driven less than 1000 miles since the motor was redone) so I have some concern is that am I running too much compression. I don't think I'm at zero-deck, but I honestly don't remember the details of that build. I do believe there are valve-reliefs in the pistons. If I am too high, would you recommend swapping pistons, opening up combustion chamber on my #12 heads, or going with bigger chamber heads (like 6X). I really want the car to look 100% stock, but I don't want to do any damage to the original heads.

If I was going to swap heads, would it then just make sense to pull out the WS and put it away, and build a 'play' engine? I have a 428 that was in my '67 HO car (which is undergoing a full restore now and going back to the stock WS motor).

Thanks for any feedback

[north]

If I were in your situation and assuming you have a 3.55 gear, M-20 powertrain I'd go for the 428 and put the factory engine in a nice safe corner of the garage. That way you protect the value of the car and you'll benefit from the extra cubes (a 60 over 428 is actually 440). The extra stroke will give you a noticeable difference in bottom end grunt and you can take the opportunity to get your compression ratio to about 9.25-9.5. One thing is if the 428 is a 67 you might be better served by switching to a set of open chamber 68-70 heads like (48-62, 12, 13, 16 etc). Those heads seem less ping prone than the closed chamber of earlier vintage. Another variation on a 428 block is to put in a 455 crank and 71 D port GTO 400 heads (96). This gets you to a nice 9 and a bit compression ratio without custom pistons or headwork. The crank might not cost more than what you'd spend extra getting the right pistons and/or head milling done to achieve target compression.

[racerboy]

THanks North. The irony is that i pulled the WS out of my 1967 back in 2000 and replaced it with the 428, and just never got around to replacing the original ' 67 WS motor until now (frame-off restoration just about done). It's a '69 YH 428, that is was over-cammed with 670 heads. I would definitely opt for larger chamber heads, though I like the ide of opening hte hood and seeing #12 heads there. Would it be possible to run those (or another set and keep mine in safe-keeping) and still run pump gas?

[north]

Number 12 heads while rated by Pontiac as 10.5 are really in the 9.5-9.75 range. Still a bit high for our crummy 2018 gas. The easiest solution is to buy custom pistons or to have stock piston relief valves enlarged.. I would avoid monkeying with the combustion chamber volumes of relatively hig value heads like 12’s.

[ponyakr]

Yeah, I vote for bagging the 400.

If you really wanna use #12 heads, I'd go with dish pistons, to get to 9.5 or slightly less CR.

My choice would also be a 4.21" or 4.25" stroke crank. That makes a very streetable 400hp/500 torque engine, easy to build.

But, a 4" stroke can also make good power.

Might be worth selling your 428 & going with a good #481988 400 block & stroker assembly. ?

Lots of options.

"...What's a good flat-tappet replacement for the 068?..."

Lunati 10510312.

http://www.lunatipower.com/Product.aspx?id=1759&gid=278

Then if you just wanna go with more lift, there's the Summit 2801. Then the Summit 2802 has more lift & duration. The Summit cams are the cheapest decent cams I know of.

Cliff has mentioned using the Crower 60243 in some hot 400's. That Crower is one of the highest priced Pontiac HFT cams I know of. Just below that might be the Crane 283951. It's cheaper than the Crower, & Summit shows to have one that can ship tomorrow.

https://www.summitracing.com/parts/c...IaAusEEALw_wcB

Then Paul Carter recommends a Voodoo series cam for almost everything. Obviously, any performance cam will need adequate valve springs.

[Jay S]

Of the choices my vote would be for a camshaft swap. Sounds like you have a very nice motor built already. I understand why some pull original engines and run another non matching motor. If your going to relentlessly beat on the car, I would say that is a good idea. If your going to cruise and occationally beat on it I would run the original motor if it is built good, which sounds to me like it is.

You can pick a lot better cam than a 068. Both performance wise and too run higher compression. The 60916 would be ok. Probably not much better than the 068 for detonation. The 60243 would be better imo. Rhoads vmaxs give you some extra tuning capabilities. The 041 would be safer yet if you want to keep it from pinging, your compression might actually be on the low side for the 041 in a 400.

For a Hyd roller probably look at one of the custom butler compcams. I can’t remember the seat timing, but I think it is 230/236 at .050, with a 112 to 114. Either lsa would work, 114 a little safer on pump gas.

Not wanting to side step other opinions here. Nothing wrong with building a bigger cid motor and save the original. Just thought I would mention some other options.
Jay

[Jay S]

This is the cam I would use for hyd roller

https://butlerperformance.com/i-2936...tegory:1272239

[racerboy]

THanks for the feedback Jay. This car is unlikely to ever see a drag strip. It's more for 'cruise nights' or going for ice cream rides, I just want it to run better and when I open up the secondaries, I want it to feel lit push me back in hte seat. If I did a hydraulic-roller swap, do I have to do any machining to the block or install any oil restrictors, or is that only for solid cams?

[John Milner]

I personally would use the 400 if you have already built it up with good internals. A cam swap would be easy to do. A cheap summit 2802 cam would make a strong runner. It will also run fine on 91 octane assuming your compression is stock. I'm assuming you have a 4 speed and 3:55 gears too. So, you can definitely get away with a bigger camshaft.

There would also be nothing wrong with pulling the original engine and running the 428, though. They are really strong running engines. I would not hesitate to run 670's or your 12's with the 428, assuming they have the factory style pistons. I have been running the small chambered heads for years on a 428 and running 91 octane fuel.

[Jay S]

No machine work involve for a hyd roller. So long as you get the Pontiac style lifters with the higher oil band. Which is what compcams uses.

The oil restricters are for solid cams. You can run oil restricted push rods on a hyd roller. Many run oil restricted push rods in conjunction with roller rockers.

Doesn’t sound like the engine has that hard of life. It still sounds like the original engine could stay in the car with no worries.

That Summit 2802 would be a good cam, durations are similar to a 744. I would suggest that over the 60916 crower. 2802 is probably the smallest cam that it would be worth the effort to do a cam swap.

Jay

[nmoreilly]

I wouldn't rule out one of the SD HR cams. The Road Paver might be a little too much with CR objective you have in mind.

http://www.sdperformance.com/listPro...p?categoryID=2

[tom s]

If me with a 400 I would use the SP cam for SD.Tom

[racerboy]

Originally Posted by tom s

If me with a 400 I would use the SP cam for SD.Tom

Thanks for the feedback. What is the ‘SP’ cam.

Also, I’m assuming that if I go the cam swap route, I will need new springs as well. I’ve never actually done that. Is it difficult? Do the heads have to come off the engine?


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[tom s]

The smaller hyd roller cam form SD performance.You will need the complete kit.Cam,lifters and springs.Tom

[north]

The trade off with cams is the "bigger" cams (longer duration) are more forgiving on octane needs but the reason for this is because the higher duration valve events reduces cylinder pressure which weakens bottom end power. Also some aftermarket moderate cams claim to be more forgiving with octane as well, they achieve this goal often by increasing the overlap, this also lowers cylinder pressure, reduces low rpm power less than high duration cams but the price you pay is an unpleasantly eratic idle which is not a big deal with a 4 speed but can be annoying with an automatic especially if you run AC.

If you are running 3.55 gears and an M20 and the car is probably 3,800 pounds I'd be hesitant to go beyond 068 type duration if you want a stout midrange engine (say no more than 200 and 225 duration at 50 thou). If you are not happy with the performance it may be be because you have too much cam, especially if you are expecting a nice 2,000-4,000 torque sweet spot.

[tom s]

SP is 230-236 on a 112 and should be no issue with a 400,less cam than a RA IV.I would be concerned with your compression ratio unless you know what your dealing with for pump gas no matter what cam you run.Tom

[Jay S]

Not really a fan of using overlap to blead cylinder pressure on a street engine. Adding Overlap is really not what I would call bleading cylinder pressure. More overlap opens the intake valve up earlier while the piston is coming up on the exhaust stroke. The intake air at low piston speed (low rpms) is getting slowed down becuase the piston is coming up, not down, some air is even sent the wrong direction (reversion). It bleads cranking pressure for say a compression test. But once the reversion stops and the overlap starts to scavenge more air it will have higher cylinder pressure.

The wide lsa’s moves the intake events farther into the compression stroke because the compression is triggered by the intake valve shutting. Effectively shortening up the what the engine can use to make compression.

Overlap bleads cylinder pressure using reversion until reversion is overcome by air velocity. Shutting the intake later bleads cylinder pressure by changing the engines ability to build compression.

No doubt the SD cams could make more power than the cam I listed from Butler. That SP cam is similar specs with more area under the curve. Only thing I would be concerned about is the extra area under the curve builds more cylinder pressure earlier in the power band, making the compression problematic again. Might be fine. I am sure Dave at SDP has done it before.
Jay

[tom s]

The last SP cam I used in a stock iron headed 455 it did not liked being advanced where Dave said to install it.Pulled it back 3 degrees and it lowered the pumping compression and made more HP.Have not used one in a 400 but it is a touch smaller than the one I put in my 366 V engine and it drove great with a 3.31 rear gear and a TKO 500.I for sure would try one in a 400 with a 3.55 rear and a M20.JMO,Tom

[racerboy]

Originally Posted by tom s

SP is 230-236 on a 112 and should be no issue with a 400,less cam than a RA IV.I would be concerned with your compression ratio unless you know what your dealing with for pump gas no matter what cam you run.Tom

How do I determine this? This weekend I will go through the photos of my 400 build. I’m pretty sure these pistons have valve reliefs, but not a dish. I believe i misspoke earlier in the thread - they are likely at zero-deck. I do remember when the shop built my 1967 HO engine, they used a dished piston, but that was done more recently than this motor.


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[tom s]

Would have to know the specs of the head CCs,pistons in the hole and gasket thickness etc.Tom