[V8Horseman]

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.

[jokerZ71]

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.

[ericnova72]

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.

[jokerZ71]

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.

[jokerZ71]

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.

[jokerZ71]

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.

[V8Horseman]

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???

[jokerZ71]

Originally Posted by V8Horseman

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.

[V8Horseman]

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.

[jokerZ71]

Originally Posted by V8Horseman

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.

[V8Horseman]

Originally Posted by jokerZ71

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.

[ericnova72]

Originally Posted by V8Horseman

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"

[V8Horseman]

Originally Posted by ericnova72

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.

[jokerZ71]

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.

[V8Horseman]

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...