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Discussion Starter · #1 ·
I know some are better than others, but I don’t personally know how to tell the difference.

I’m looking for a decent set of 64cc heads and found these:


Are these of the decent variety? They look like they might be the same casting as the AFR enforcer, but I really don’t know how to tell them all apart.

any input?
 

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Discussion Starter · #3 ·
Those are the good ones. Same casting as the enforcer head. You can buy a kit from competition products to fill them up with valves, seals, Springs, and retainers.
thanks.

that is the plan, to get a kit from competition products and have them checked out by a machine shop. Worth the money to have someone assemble them correctly I think.

I just struggle with knowing the good from the not so good.
I’ve got these saved so when the time comes I can find them.
 

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These are decent heads and quite popular, they only bolt to the classic 1955-1986 intake pattern.

You will need to purchase valves that are .1 inch longer than stock GM. As typical with aftermarket aluminum heads the entire spring assembly is positioned that much higher from the head gasket surface. This also requires push rods that are .1 inch longer than normally stock.

The valve spring assemble from bottom to top require a spring seat as the steel spring will eat the softer aluminum without a spring seat, guide/stem seal, spring itself, spring retainer, and locks.

- The spring seat can be a cup or a locator:
  • The cup which is shaped like a shallow saucer with a central ID hole and a raised OD edge. Sizing these The ID hole needs to fit over the guide boss OD. The cup OD rim needs to fit the spring OD and within that of the pad’s machined edges.
  • The locator has a collar that has to have an ID that fits over the guide OD and fits inside the spring ID this can be tricking to a non player with nested springs but works well with beehives. The base as with the spring cup needs to fit inside the machined spring pad OD. Additionally the collar needs to be low enough to not interfere with seal installation.

All of this spring seat measuring and selecting is probably the biggest headache of doing bare head stuffing yourself. You will find that the fits of the spring seat are in close enough to get the job done not in precise fits as you think of as machine part clearances.

- Guide seals need to fit the guide boss and stem diameters while providing for lift clearance to the underside of the retainer. Unless you’re running lifts over well .5 inch this usually isn’t a problem.

- Springs need to be decently matched to the cam, here I’m not talking roller or flat tappet but rather if your chosen cam requires special springs by the manufacturer. Generally short of all out competition cams I like beehives. They do more work across a broader range of lobe and lifter designs with less pressure. You have to keep in mind that beehives are really designed for metric valves so when matching them to the 11/32nd standard SBC valve stem you need a retainer that bridges this metric spring to US like the Comp 767-16. It’s done a lot.

- Your retainer choices are going to match your performance level and spring size and type.

- Locks need to match retainer and valve stem, here again this depends on how you use the engine more than less standard lock uses a 7 degree angle where super duty racing parts use 10 degrees. This in addition to previously mentioned constraints is going to affect the retainer choice.

So pretty much going on your own with bare heads this is the rocket science you need to get into. Follow this link and order up their free paper catalog it is a gold mine of information that is hard to come by otherwise.


Bogie
 

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Wow! Are you guys sure those are decent heads for less than $374/pair + free shipping? That sounds like 1990s prices.

Summit sells the actual AFR Enforcer heads with valves, springs, studs, and guides for around $1,200, as I recall. I recently watched a "cheap" head shoot-out on Engine Masters, and the guys were very impressed with them right out of the box. On the other hand, the Summit-branded heads were just OK, and the Speedmasters pretty much sucked.
 

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Wow! Are you guys sure those are decent heads for less than $374/pair + free shipping? That sounds like 1990s prices.

Summit sells the actual AFR Enforcer heads with valves, springs, studs, and guides for around $1,200, as I recall. I recently watched a "cheap" head shoot-out on Engine Masters, and the guys were very impressed with them right out of the box. On the other hand, the Summit-branded heads were just OK, and the Speedmasters pretty much sucked.
They are the same head casting as AFR enforcers, just AFR machines them different. And you can buy AFR Enforcers bare as well, I have a set But they take 8mm stem size valves.
 

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The big thing is valve seat support. Everybody goes to port flow first thing, but while that establishes power an inadequately supported valve seat coming lose ruins your day not to mention your engine. The Speedmaster is improved over its earlier ProComp but falls short of other import brands in this regard. For the most part the import heads power wise will match the iron Vortec. The Vortec on a 350 is an easy 380 to 420 hp head. Power depends on attention to details including cleaning the ports, compression ratio, piston crown shape, cam selection, beef in the valve train.

Bogie
 

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Procomp has a history of dropping seats But I know people who ran them and ebay generics for 1,000's of miles w/o any real issue. Tho the guides were toast pretty fast on the procomps...

The amount of aftermarket CO's that put their name on ebay generics is proof enough for me. BPE, AFR, KMJ, NKB and on n on...
 

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Hi guys, I thought I'd buy a set of these for my small block project. First off, the packaging: These heads came in one box. I opened that box to find two individually boxed heads. I opened one of those boxes to find the head encased in a Styrofoam carton. VERY well packed. Although I have not done any measuring yet, the appearance of the heads is good. The only paperwork that came with them was a sheet saying to inspect and wash them. No spec sheet. I'm a bit bummed about that.
 

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These are decent heads and quite popular, they only bolt to the classic 1955-1986 intake pattern.

You will need to purchase valves that are .1 inch longer than stock GM. As typical with aftermarket aluminum heads the entire spring assembly is positioned that much higher from the head gasket surface. This also requires push rods that are .1 inch longer than normally stock.

The valve spring assemble from bottom to top require a spring seat as the steel spring will eat the softer aluminum without a spring seat, guide/stem seal, spring itself, spring retainer, and locks.

- The spring seat can be a cup or a locator:
  • The cup which is shaped like a shallow saucer with a central ID hole and a raised OD edge. Sizing these The ID hole needs to fit over the guide boss OD. The cup OD rim needs to fit the spring OD and within that of the pad’s machined edges.
  • The locator has a collar that has to have an ID that fits over the guide OD and fits inside the spring ID this can be tricking to a non player with nested springs but works well with beehives. The base as with the spring cup needs to fit inside the machined spring pad OD. Additionally the collar needs to be low enough to not interfere with seal installation.

All of this spring seat measuring and selecting is probably the biggest headache of doing bare head stuffing yourself. You will find that the fits of the spring seat are in close enough to get the job done not in precise fits as you think of as machine part clearances.

- Guide seals need to fit the guide boss and stem diameters while providing for lift clearance to the underside of the retainer. Unless you’re running lifts over well .5 inch this usually isn’t a problem.

- Springs need to be decently matched to the cam, here I’m not talking roller or flat tappet but rather if your chosen cam requires special springs by the manufacturer. Generally short of all out competition cams I like beehives. They do more work across a broader range of lobe and lifter designs with less pressure. You have to keep in mind that beehives are really designed for metric valves so when matching them to the 11/32nd standard SBC valve stem you need a retainer that bridges this metric spring to US like the Comp 767-16. It’s done a lot.

- Your retainer choices are going to match your performance level and spring size and type.

- Locks need to match retainer and valve stem, here again this depends on how you use the engine more than less standard lock uses a 7 degree angle where super duty racing parts use 10 degrees. This in addition to previously mentioned constraints is going to affect the retainer choice.

So pretty much going on your own with bare heads this is the rocket science you need to get into. Follow this link and order up their free paper catalog it is a gold mine of information that is hard to come by otherwise.


Bogie
Hey Bogie, what head bolts and rocker studs would a guy run with these heads? I bought a pair and they come without any kind of a spec sheet.
 

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Hey Bogie, what head bolts and rocker studs would a guy run with these heads? I bought a pair and they come without any kind of a spec sheet.
Rocker studs, depends on the rockers, I like to mock it up n see what length stud works best but I have a variety of studs. Head bolts, compared to my Sportsman II's the same amount of thread was sticking thru, so w/e that ARP part # that is should work fine.
 

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These heads do not guide the push rod so your first decision is whether to run sheet metal guides or self-guiding rockers. The consideration here is for street performance limited to the upper 5000 ending at 6000 self-guiding are fine. For an engine being twisted higher than 6k RPMs the additional weight of the self-guiding mechanism while usually just two washers is reflected into what the valve spring has to manage by virtue of their distance from the center of the rocker trunnion So this has to be considered into what the valve spring has to deal with.

For head bolts you want to shop for a longer than stock bolt specific for aluminum heads because a hardened parallel ground washer is needed between the underside of the bolt head and the softer aluminum. Installation requires the underside of the bolt head be lubricated against the washer but the underside of the washer to head is kept dry. This is so the washer doesn’t spin against the head as the bolt is torqued up. Keep in mind that the SBC‘s head fastener holes thread into the cooling jackets requiring the threads be sealed. There’s two problems to be solved simultaneously here that of sealing the threads and providing the correct thread lubrication to get the correct fastener stretch for the indicated torque. I used to prefer Teflon plumbers putty but have switched to non hardening Permatex Number 2 their part number is 80015. This is more resistant to glycol coolant than plumbers putty but either has a coefficient of friction between screw threads that is close enough to the torque spec that references engine oil on the threads.

Studs can be treated the same way for sealing into the block because using the often recommended hardening sealers risk breaking the seal if installation through torquing the nut is not completed before the sealer cures, otherwise these are risks of coolant leaks which are a pain to remedy after final assembly or a field repair. The nut takes a hardened parallel ground washer as well and the washer and nut are dry between washer and head and lubed between nut and washer. The upper threads are lubricated with engine oil or the manufacturer’s recommended thread lube.

These heads will before porting deliver almost identical to the L31 which with attention to the details of valve train parts and some minor port clean up and adjustments will easily go into 415 plus horsepower and a like amount of torque. They are not going to make the same power as the 2500 plus dollar domestic heads but will come close enough to scare the crap out of anybody so equipped.

To complete them you will need valves, springs, locators, retainers and locks this is probably the biggest mental effort but success can save you a lot of money. I think early on in this blog I suggested you order up a paper copy of the Competition Products catalog and I guess a Harbor Freight digital micrometer. Your going to need to measure the valve guide OD for both the stem seals and for either a spring locator or cup. The locator has an inside collar that locates around the guide OD and has to provide vertical space to fit the stem seal above it so need to know the height of the guide from spring pad to top of the guide and the dstance from the upper end of the collar to the top of the guide. One advantage is aftermarket headsgenerally don't have retainer to seal clearance problems. The other critical dimension you need is the machined OD of the spring pad as whether you use a locator or cup it has to seat inside the edges of the machined spring pad. Also you need the spring ID and OD. The spring ID has to fit past guide, the seal and if used the locator collar. The cup is less a problem in this regard but it’s diameter just inside the lip should be close to the spring OD. In both cases we’re trying to keep the spring on a steel pad as it would eat the soft aluminum. In the case of the locator the collar back stops the springs sideways movement from the inside where the cup hugs the spring OD at its base, needless to say with the cup a spring in crazy surge can override the cup lip and break. So if your going to rev to where the valve springs get unstable the locator is a safer way to keep things intact, but in the real world available space is the final arbiter.

I actually have a set of ebay heads in the shop that I have parts to build them out so if you get a set and I can figure out how to get pictures off my IPad onto this site I can walk you through this.

Bogie
 

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These heads do not guide the push rod so your first decision is whether to run sheet metal guides or self-guiding rockers. The consideration here is for street performance limited to the upper 5000 ending at 6000 self-guiding are fine. For an engine being twisted higher than 6k RPMs the additional weight of the self-guiding mechanism while usually just two washers is reflected into what the valve spring has to manage by virtue of their distance from the center of the rocker trunnion So this has to be considered into what the valve spring has to deal with.

For head bolts you want to shop for a longer than stock bolt specific for aluminum heads because a hardened parallel ground washer is needed between the underside of the bolt head and the softer aluminum. Installation requires the underside of the bolt head be lubricated against the washer but the underside of the washer to head is kept dry. This is so the washer doesn’t spin against the head as the bolt is torqued up. Keep in mind that the SBC‘s head fastener holes thread into the cooling jackets requiring the threads be sealed. There’s two problems to be solved simultaneously here that of sealing the threads and providing the correct thread lubrication to get the correct fastener stretch for the indicated torque. I used to prefer Teflon plumbers putty but have switched to non hardening Permatex Number 2 their part number is 80015. This is more resistant to glycol coolant than plumbers putty but either has a coefficient of friction between screw threads that is close enough to the torque spec that references engine oil on the threads.

Studs can be treated the same way for sealing into the block because using the often recommended hardening sealers risk breaking the seal if installation through torquing the nut is not completed before the sealer cures, otherwise these are risks of coolant leaks which are a pain to remedy after final assembly or a field repair. The nut takes a hardened parallel ground washer as well and the washer and nut are dry between washer and head and lubed between nut and washer. The upper threads are lubricated with engine oil or the manufacturer’s recommended thread lube.

These heads will before porting deliver almost identical to the L31 which with attention to the details of valve train parts and some minor port clean up and adjustments will easily go into 415 plus horsepower and a like amount of torque. They are not going to make the same power as the 2500 plus dollar domestic heads but will come close enough to scare the crap out of anybody so equipped.

To complete them you will need valves, springs, locators, retainers and locks this is probably the biggest mental effort but success can save you a lot of money. I think early on in this blog I suggested you order up a paper copy of the Competition Products catalog and I guess a Harbor Freight digital micrometer. Your going to need to measure the valve guide OD for both the stem seals and for either a spring locator or cup. The locator has an inside collar that locates around the guide OD and has to provide vertical space to fit the stem seal above it so need to know the height of the guide from spring pad to top of the guide and the dstance from the upper end of the collar to the top of the guide. One advantage is aftermarket headsgenerally don't have retainer to seal clearance problems. The other critical dimension you need is the machined OD of the spring pad as whether you use a locator or cup it has to seat inside the edges of the machined spring pad. Also you need the spring ID and OD. The spring ID has to fit past guide, the seal and if used the locator collar. The cup is less a problem in this regard but it’s diameter just inside the lip should be close to the spring OD. In both cases we’re trying to keep the spring on a steel pad as it would eat the soft aluminum. In the case of the locator the collar back stops the springs sideways movement from the inside where the cup hugs the spring OD at its base, needless to say with the cup a spring in crazy surge can override the cup lip and break. So if your going to rev to where the valve springs get unstable the locator is a safer way to keep things intact, but in the real world available space is the final arbiter.

I actually have a set of ebay heads in the shop that I have parts to build them out so if you get a set and I can figure out how to get pictures off my IPad onto this site I can walk you through this.

Bogie
Thanks for the advice Bogie. I did a bunch of measuring on the heads and went to competition products for the parts needed to assemble them. These heads can handle a 1.5" spring but I'm going with smaller ones so I'll be using spring cups that fit the valve guides. Before I order parts if I want to go with self guiding rockers, do I need a certain retainer? This engine is in a cruiser that will never see the higher side of 5000 rpms.
 
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