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Discussion Starter #1
In the process of picking heads for a new 355 sbc with 10.5:1 compression, Comp cams High Energy 268h. I'm currently trying to decide between Edelbrock Performer RPM PN: 60735 or ATK PN: sbc70185. Any advice would be greatly appreciated.
 

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Wrench Turner
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Take a look at the Profiler 185.Very good American head.Similar flow rates as an AFR, but, $300 to $400 lighter on your wallet.They run $1050 a set bare, or, $1125 assembled. You'll be just over $1200 with taxes & shipping.
Don't know much about the ATK heads.
 

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The ATK head is using the Pro-Filer head casting as its core. Only difference is a stock location exhaust port, ProFiler has a raised exhaust port. Made special just for ATK.

Far better than the Edelbrock Performer RPM, you'd have to get an Edelbrock Victor head to even get anywhere close to the ATK.

Edelbrock heads are under-achieving for their price IMO. You're paying more for their name and getting less for it.
 

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Wrench Turner
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That dyno chart is based 9.25:1 compression & Dart S/R cylinder heads.A very far cry from the final outcome of 10.5:1 motor with a decent set of heads.
 

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Wrench Turner
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Dart S/R heads are not much more than stock smog heads.Is it not you who claims 40 to 50 HP increase just from bolting on a set of aluminum heads.It's also using a standard Performer intake.Those dyno charts are based on what the average smog headed,low compression street motor will accomplish setup with that cam.That info comes from Comp.It is provided to show what the average low compression factory motor will accomplish with this cam & setup as demonstrated in the dyno.That's why they supply all of the supporting parts & compression.
With a set of Profiler,or,even a set of Vortecs for that matter & appropriate compression ratio for either head,he has an easy 375 HP & more than 400 ft/lb.
That dyno chart in no way represents the actuality of what the OP's motor will be capable of.
 

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Wrench Turner
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I would say your compression matches up very well with this cam.With any of the heads listed so far,you should be able to hit 375 to 385 HP easily & should be no problem with detonation at all with aluminum heads & proper tuning.The setup will still be very docile & streetable.
If you don't already have the cam,take a look at Lunati's 268 cam.
 

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Discussion Starter #7
My dad had originally built the 355 short block back in the 90's and bought the cam specifically for use in his Corvette. He never ended up using it and instead dropped in a built 383. I bought the short block and cam off him and plan on dropping it into a 1966 caprice mated to a th400 w/gear vendors unit. Power goals are 350 hp 380tq. Car will be driven daily throughout spring summer and fall. I'm not familiar with a raised exhaust port location on the pro-filers, does that mean only certain special parts can mate up with the raised port???
 

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Wrench Turner
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My dad had originally built the 355 short block back in the 90's and bought the cam specifically for use in his Corvette. He never ended up using it and instead dropped in a built 383. I bought the short block and cam off him and plan on dropping it into a 1966 caprice mated to a th400 w/gear vendors unit. Power goals are 350 hp 380tq. Car will be driven daily throughout spring summer and fall. I'm not familiar with a raised exhaust port location on the pro-filers, does that mean only certain special parts can mate up with the raised port???
A vortec type intake will match up & be easier to seal up with the raised ports.
You should have no problems hitting that goal with just about any modern aluminum head & your cam combo.You have to try not to,in order to fail.
that combo is prolly 1 of the most widely used combos among street 350"s.It's a very common setup.
 

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Discussion Starter #9
So Any vortec intake will work? Or are there only certain ones I should look for. Also I'm not sure what the internal specs are on the motor, my father said the pistons in it are built to mate up with a 70cc chamber, that's about all I know. I believe he was planning to use the Eddy Performer RPM heads on it originally, that's why I was looking at those specific part numbers on both the ATK and Eddy heads listed in the first post.
 

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Wrench Turner
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So Any vortec intake will work? Or are there only certain ones I should look for. Also I'm not sure what the internal specs are on the motor, my father said the pistons in it are built to mate up with a 70cc chamber, that's about all I know. I believe he was planning to use the Eddy Performer RPM heads on it originally, that's why I was looking at those specific part numbers on both the ATK and Eddy heads listed in the first post.
It will really depend on the actual head itself.you won't be able to use an actual Vortec intake,unless your heads have the 8 bolt pattern specific to Vortec heads.Some heads do have both bolt patterns.With something like the Profiler 185,a normal Performer RPM intake should be fine.If you went to a larger port like over 200cc,you may have some issues.For your build,if this is a strictly street car with no serious track time,i would stay with a 185 cc head.
You really need to figure out for sure what the compression will be before you order heads.Try to ID the pistons & their type(flat top?dish?)volume in cc's,along with measuring how far down the bore they set at TDC.This is very important I can't stress that enough.
If your actual compression is truly 10.5:1,the timing of that cam will have you rite where you need to be for a street driven aluminum headed engine.You will be in a safe range & be able to tune for the best performance without worrying about detonation.
 

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Discussion Starter #11
It will really depend on the actual head itself.you won't be able to use an actual Vortec intake,unless your heads have the 8 bolt pattern specific to Vortec heads.Some heads do have both bolt patterns.With something like the Profiler 185,a normal Performer RPM intake should be fine.If you went to a larger port like over 200cc,you may have some issues.For your build,if this is a strictly street car with no serious track time,i would stay with a 185 cc head.
You really need to figure out for sure what the compression will be before you order heads.Try to ID the pistons & their type(flat top?dish?)volume in cc's,along with measuring how far down the bore they set at TDC.This is very important I can't stress that enough.
If your actual compression is truly 10.5:1,the timing of that cam will have you rite where you need to be for a street driven aluminum headed engine.You will be in a safe range & be able to tune for the best performance without worrying about detonation.
Thanks for the info I will examine the engine this weekend, and plan from there.
 

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I'm not familiar with a raised exhaust port location on the pro-filers, does that mean only certain special parts can mate up with the raised port???
Header to chassis clearance, as well as clearance for the steering box and steering shaft can be an issue sometimes when using raised exhaust port heads. The port outlet being raised makes the headers sit a little higher in the engine bay, which can be a problem is some smaller engine bays like the 62-87 Chevy II, sometimes the 67-69 Camaro and 68-74 Nova. With your big car, it would be a non-issue.

The ATK head has the exhaust port in the original factory location, at their request. The ProFiler that is sold direct from ProFiler has a raised exhaust port.

The raised port deal is just to increase exhaust flow.

Small Blocks with 23° heads raised ports are typically raised .100", Big Blocks .200"-.400"
 

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Discussion Starter #13
Header to chassis clearance, as well as clearance for the steering box and steering shaft can be an issue sometimes when using raised exhaust port heads. The port outlet being raised makes the headers sit a little higher in the engine bay, which can be a problem is some smaller engine bays like the 62-87 Chevy II, sometimes the 67-69 Camaro and 68-74 Nova. With your big car, it would be a non-issue.

The ATK head has the exhaust port in the original factory location, at their request. The ProFiler that is sold direct from ProFiler has a raised exhaust port.

The raised port deal is just to increase exhaust flow.

Small Blocks with 23° heads raised ports are typically raised .100", Big Blocks .200"-.400"
I appreciate the explanation thanks.:thumbup:
 

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Wrench Turner
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Thanks Eric for clearing that up.I admit that I was preoccupied at work earlier before realizing that the OP & me were talking about 2 different things.I was thinking intake ports & he was referring to your comments about exhaust ports on the ATK head.
A bad case of not paying attention.
 

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Discussion Starter #15
So has any one here ever used ATK sbc heads on one of there builds with success? You tend to hear alot about Edelbrock stuff, but it seem to be a differant story when searching for ATK. Just curious because Summit has ATK's with the 70cc chambers that I need, and 195cc intake runners for little over $100 less then the equivalent Edelbrock heads...
 

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Discussion Starter #16
Thats an expensive head from a none head builder like atk. they rebuild engines as a main focus.

SBC CHEVY 327 350 383 NKB-200cc ALUMINUM HEADS 64cc STRAIGHT PLUG NKB-272 | eBay

How about a head a lot cheaper than both 699 a set. Thats for both heads not just one like summit. Flow is about the same or better as edelbrock and built with good parts. I have used a set of heads from the seller but not these. some on here have and liked them a lot. for the money there a great head. They can also get ported out for some amazing flow numbers later on if you want to upgrade.

Spend the savings on a roller cam. this will make the build a lot better than the flat cam and more expensive heads. Also a lot more reliable as well the flat cams with the steep ramps tend to wipe more often than the slower ramp cams.

I have purchase an engine from atk it was OK not great not better than new just ok. Compression was all over the place but not really bad. Other have had less luck some better. If its a profiler head i would just buy from them instead of atk version of it. They make a good head your basically paying for markup. Since its been sold twice. First to them then to you. Go straight to the source if you want one of there heads.

If you got the bucks afr is a great head.

AFR CHEVY SBC 383 406 ELIMINATOR HEADS 195cc 65cc FULLY BUILT # 1034-HR St. Plug | eBay

these are afr heads and worth the money to upgrade. But really not needed for most builds and with your cam choice its not going to provide a whole lot more.

Hope this helps.
Hmm NKB heads eh? They do look like a nice head, though I'd need 70cc chambers instead of 64's. Believe me if I had the money I'd love to invest in a set of AFR's. But I'll give these NKB's a closer look Thanks for the info.
 

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So has any one here ever used ATK sbc heads on one of there builds with success? You tend to hear alot about Edelbrock stuff, but it seem to be a differant story when searching for ATK. Just curious because Summit has ATK's with the 70cc chambers that I need, and 195cc intake runners for little over $100 less then the equivalent Edelbrock heads...
You can look up some builds here using the ProFiler heads, the ATK would give near identical results.

• Index page

More ProFiler info here: Speier Racing Heads - SRH Home/Contact

The ProFiler 195cc head in as-cast for is within 5cfm of a fully CNC ported AFR 196cc Eliminator head up to .500" lift. The ProFiler and ATK are $500 less costly.

Just to let you know that not everyone thinks AFR is the be-all and end-all when it comes to SBC cylinder heads.
 

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Discussion Starter #18
You can look up some builds here using the ProFiler heads, the ATK would give near identical results.

• Index page

More ProFiler info here: Speier Racing Heads - SRH Home/Contact

The ProFiler 195cc head in as-cast for is within 5cfm of a fully CNC ported AFR 196cc Eliminator head up to .500" lift. The ProFiler and ATK are $500 less costly.

Just to let you know that not everyone thinks AFR is the be-all and end-all when it comes to SBC cylinder heads.
Many thanks for info, I didn't know ProFiler's could flow that well. ATk's do still seem like a decent head, so I'll keep them on the table for now.
 

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Discussion Starter #19
Are you sure you need 70 cc heads. I wonder if the heads really need to be 70cc how did you figure your compression. The heads on the market that are 64 and 65 cc its real common for that to be the right size head for the 350. I have flat tops and 58cc heads and barley get 11:1

I posted a link for a calculator to help figure this out the pistons and most manufactures compression figures are often just round about and not accurate.
But you can get the nkb in 68 cc heads. mostly for 383 with flat tops to get the right compression.

I would not be surprised the compression of your motor will be a lot lower than 10.5:1 with a 350 and 70cc heads.

I suggest the nkb's because they are cheapest good heads on the market. The Afr because they have the best rep and proven power makers. Lots of choices in between but really its either the best or cheap for me.

A roller cam is a big step up in performance over the flat hydro. So its worth saving a few bucks and getting a good cam setup. Its the brains of the motor not the best place to save cash.
I'm certain the builder we had gotten the short block from 20 years ago had built the engine for 10.5:1 comp with 70cc Edelbrock Performer RPM heads, of course I will be verifying this before I actually buy anything.
 

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Wrench Turner
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Not sure what the overbore is.You may said, but, about the only way to get 10.5:1 on 350 with 70 cc heads would be either with a slight dome, or, a true flat top with no valve relief at 0 deck.If it is a dome, you will have to be careful with head selection & chamber shape.The modern heart shaped chambers used in most performance heads now will not work with old school type dome pistons.
As for heads, like I said earlier, I don't know alot about the ATK, but, if it is indeed the same casting as the Profiler, it should be a great head & even if the costs are more, it is still a far superior head to any of the budget import heads.The Profiler is available in 64, or,72 cc.If you do indeed need a 70 cc head, the extra 2 cc is not gonna make a big difference whatsoever. You need to for sure determine the piston type & volume tho on your shortblock.
 
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