[Will]

lethal Lemans asked a similar question in another thread. Judging by what he's written and the questions he's asking, I think we need to take a step back here and get some answers to some questions first.

Is this engine being rebuilt? Are you having the block machined, installing new pistons, etc.? What about the heads? Ideally you'd have some work done to them to set them up for what you want to do. This would include new guides if necessary, new valves for sure (stock/factory valves are a ticking time bomb), cutting the seats, having the guides machined for positive seals and selecting the right springs for the cam & rockers you want to run.

What car is it going into and what gears/transmission are you working with?

What is your goal for the overall performance of this car? Do you want it to have decent idle vacuum? Be able to run A/C? Be very driveable in pretty much all conditions? Or, are you more interested in a max performance street car and are willing to do what you need to do if vacuum is too low for power brakes?

Do you have a performance goal in mind? How fast you want to go and how you want the car to behave is more important than any particular horsepower number.

In your other post you were asking whether you should run headers or RA manifolds. That says to me that your more concerned with a streetable combo than a max power effort, but it would be good to get it all out in the open and have all the facts.

[chiphead]

Agreed. The temptation for a hobbyist is to assume a lot of parameters and go right for the cam selection, damn the torpedoes. I've found that choosing and setting static compression first is the better idea. That means you've got to choose engine size, confirm chamber size, and then select pistons and machine work to hit the mark. Then choose cam based on engine size, known cr, drivetrain and car weight.

If you're doing a cam swap on a running engine,. It's still a good idea to challenge the assumptions on the compression, what valvetrain parts are required, etc.

[lethal-428-lemans]

My goal is a good all around car that is fun to drive with lots of power. The idle is not super important but it would be nice to be able to run power breaks. It's a 64 tempest post had a 6 cylinder with a power glide that scaled in at 3560 with me in it.

I picked up a tko GM 5 speed 1st 3.27 , 1.98 , 1.34 , 1.00 , 0.68 over drive. Rear gear is 3:90 . The 400 was running fine I just wanted to freshen it up and get a little more out of it for this year. I asked about the headers or ram air manifolds because I hated the constant tightening on them on my 428 and was told the manifolds were just as good as headers. My plan was to change cam , lifters and springs in the car like I did the 428.

I have another 400 with #16s that I'm going to build a power house out of down the road. But for know the plan is just a fun car that can hold its own on the streets that I can enjoy.

[Will]

Okay, so just a cam swap in an already running engine, got it.

The manifolds will cost a little power over headers, but how much will depend on how big of a cam you go with and what the lobe separation is. Narrow LSA cams (I'm going to call narrower than 110 "narrow") will lose more power with the manifolds than wider lSA cams will. The wider the LSA a cam is ground with, the less sensitive it is to exhaust pulse tuning and in general will idle a bit better and have a broader, less peaky powerband. Cams with narrower LSAs really need good, unrestricted airflow through the intake and exhaust tracts to work best. They can make very broad powerbands if the airflow is there though they will almost always have rougher idles and lower vacuums than a cam with the same duration on a wider LSA. This is all "generally speaking," there can be exceptions to everything, but that's how it works in general.

Given that you're not porting the heads and you want enough vac. for power brakes you can't make use of a really big cam. I think if you go with manifolds I'd stand by my previous recommendation of the Crower 60916 for this application. It'll make a lot of midrange power. If you go with headers, stepping up to the Crower 60243 or the Lunati cam that Pastry Chef mentioned makes sense.

If you are willing to run Rhoads lifters you can step up a bit more in either scenario. The bigger cam would work okay with the manifolds and you could go even a bit bigger yet, into something in the very low 230@ .050" range with headers. Any more cam than that is kind of a waste of time with stock heads in a street car. Is the bottom end of this engine stock? If so, you want to consider reasonable RPM limits (5700 or below) to keep from breaking things so again a much bigger cam doesn't really work.

With stock length valves the Crower 68404-16 springs will work fine with any of those cams. I would stick with stock rocker arms or go to a full roller rocker, and not one of the cheapo brands either. Harland Sharp are probably the best compromise between cost and durability for a street car.

Be sure to get the guides cut for positive seals and then ditch the stock oil shields on the springs. Stock retainers and keepers are fine, though be sure to measure retainer to seal clearance at max lift. You can grind a bit off the stock retainers for clearance if necessary.

That's my opinion, worth every penny you paid for it.

[lethal-428-lemans]

Originally Posted by Will

Okay, so just a cam swap in an already running engine, got it.

The manifolds will cost a little power over headers, but how much will depend on how big of a cam you go with and what the lobe separation is. Narrow LSA cams (I'm going to call narrower than 110 "narrow") will lose more power with the manifolds than wider lSA cams will. The wider the LSA a cam is ground with, the less sensitive it is to exhaust pulse tuning and in general will idle a bit better and have a broader, less peaky powerband. Cams with narrower LSAs really need good, unrestricted airflow through the intake and exhaust tracts to work best. They can make very broad powerbands if the airflow is there though they will almost always have rougher idles and lower vacuums than a cam with the same duration on a wider LSA. This is all "generally speaking," there can be exceptions to everything, but that's how it works in general.

Given that you're not porting the heads and you want enough vac. for power brakes you can't make use of a really big cam. I think if you go with manifolds I'd stand by my previous recommendation of the Crower 60916 for this application. It'll make a lot of midrange power. If you go with headers, stepping up to the Crower 60243 or the Lunati cam that Pastry Chef mentioned makes sense.

If you are willing to run Rhoads lifters you can step up a bit more in either scenario. The bigger cam would work okay with the manifolds and you could go even a bit bigger yet, into something in the very low 230@ .050" range with headers. Any more cam than that is kind of a waste of time with stock heads in a street car. Is the bottom end of this engine stock? If so, you want to consider reasonable RPM limits (5700 or below) to keep from breaking things so again a much bigger cam doesn't really work.

With stock length valves the Crower 68404-16 springs will work fine with any of those cams. I would stick with stock rocker arms or go to a full roller rocker, and not one of the cheapo brands either. Harland Sharp are probably the best compromise between cost and durability for a street car.

Be sure to get the guides cut for positive seals and then ditch the stock oil shields on the springs. Stock retainers and keepers are fine, though be sure to measure retainer to seal clearance at max lift. You can grind a bit off the stock retainers for clearance if necessary.

That's my opinion, worth every penny you paid for it.

Can I do the guides with the heads still on the car ?

[chiphead]

No, the guide work needs to be done with the valves removed.

If these are stock (tall) guides, you MUST verify retainer to guide clearance at max lift of cam. Otherwise the retainer hits the guide and massive parts breakage results. Valve lifts over .450 start to get into trouble unless you check. every. one. for adequate clearance of .090".

Read very carefully to understand the basics:

http://www.lunatipower.com/Tech/Valv...pringTech.aspx

[lethal-428-lemans]

I'm going to get the Rhoda's lifters and the crower 60243 now what would be my best bet on valve springs ? Is any supplier better than another ? Any suggested part numbers ?

[ponyakr]

"...what would be my best bet on valve springs ?..."

If your installed spring height is 1.6, then go with Crower 68404-16 springs.

http://www.jegs.com/i/Crower/258/68404-16/10002/-1

If the installed height is 1.7, go with Comp Cams 995-16 springs.

http://www.ebay.com/itm/Comp-Cams-99...38.m2548.l4275


"...Any suggested part numbers ?..."

Here's the original Rhoads lifters, with the Super Lube groove added.

https://www.summitracing.com/parts/r...w/make/pontiac


"...the crower 60243..."

The best shipped price I can find is $162.40 direct from Crower.

https://www.crower.com/pontiac-287-4...m-284-hdp.html

If you need the 68404-16 springs, you can get a free ride for 'em, along with the cam, and save a few cents.

https://www.crower.com/valve-springs...-dual-823.html


"...Is any supplier better than another ?..."

Summit says they'll beat any shipped price. So, you might be able to save a few more cents, and buy the cam, springs & lifters from Summit.

"We'll beat any advertised price on an In-Stock product (with proof of the advertised price) if the part is In-Stock at the advertised location."
*Advertised price includes all shipping, handling, or any other "to the door" costs.*
This policy DOES NOT apply to:
Typographical errors.
Products in an online auction.
Closeouts.
Damaged or "Open Box" items.
Discontinued, clearance, or liquidation items.
Refurbished or used products from a second-hand seller.
Wholesale, membership, or club pricing.
A competitor's price that results from a price match.
To take advantage of our Beat-a-Price Guarantee, please Contact Us."

There may be some guys who post here who can beat these prices. If so, they can post that info.

KRE is a big Pontiac shop that sells Crower stuff. Don't know if they'll price match or not.

http://www.krepower.com/Pontiac%20Ca...nd%20Parts.htm

Len Williams is the only Pontiac shop I recognized on the Rhoads lifter dealer list.

http://www.rhoadslifters.com/Pages/dealers.html

[lethal-428-lemans]

Originally Posted by ponyakr

If your installed spring height is 1.6, then go with Crower 68404-16 springs.

http://www.jegs.com/i/Crower/258/68404-16/10002/-1

If the intalled height is 1.7, go with Comp Cams 995-16 springs.

http://www.ebay.com/itm/Comp-Cams-99...38.m2548.l4275

Here's the original Rhoads lifters, with the Super Lube groove added.

https://www.summitracing.com/parts/r...w/make/pontiac

Thank you, I'll have to measure the springs and see what a have stock.