Head and cam question

[minifridge1138]

Hey everyone,

My engine is 26 years old and is showing some signs of age. I'm not going to start tearing it apart in the immediate future, but I am trying to put together a shopping list of things i'm considering.

Does anyone have any experience with AFR Cylinder heads? I have been looking at their 180cc. The combustion chamber is 75cc which (if my math is correct) would put my compression ration at about 10.55:1 (depending on head gasket thickness.

In terms of a cam I have been looking at a comp cam part with the following stats:
Intake Exhaust
Duration (0.05 inch) 212.0 218.0
Duration (seat to seat) 256.0 268.0
Valve Lift (std rocker) 0.447 0.454
RPM Range of 1000-5200

I'm not trying to build a race car. But if i'm already going to the trouble of taking the engine apart I would like to get more power but keep pump gas.

Thoughts, comments, and crude remarks are welcome!!!

 

[Hib Halverson]

I think AFR is about the best of the aftermarket cylinder head vendors.

No doubt the cost of AFR stuff might be higher than others, but typically, AFR does the engineering and development to make its parts worth the price.

Interestingly, Tony Mamo, the guy who's behind most of the research and development at AFR is a Corvette owner and enthusiast.

If I were in the market for an aftermarket aluminum cylinder head, AFR is where I'd go to get them.

As for the camshaft, I'm partial to Crane because I think Crane has a bit of a quality edge, but generally Comp makes good stuff, too. But, be it Crane, Comp or another cam company, I can't stress enough how important proper assembly and break-in will be to your cam's durability.

Also, don't cheap out on the rest of the valvetrain. Regardless whether it's Crane or Comp, buy not only the cam but the cam and kit from the same company.

As for the particular grind you've cited, it's not possible to offer any input there because you offered no other engine details. You cannot properly choose a cam, until you set the other parts choices.

You at least need to know:
displacement
bore and stroke
compression ratio
rpm range
induction system.

 

[minifridge1138]

displacement = 350 cid
bore and stroke = 4.00 X 3.48
compression ratio = 10.55
rpm range = idle - 6000
induction system = natural aspirated carb

The compression ratio is a guess based on combustion chamber size of the heads I was looking at. I also need to stay pump gas friendly (I have access to 93 octane, but not higher).

 

[Vette79]

I completed my top-end build with AFR 180cc Eliminator Street Cylinder Heads. I had them milled to 60cc by AFR for best compression ratio. Take a look at this thread: http://corvetteactioncenter.com/forums/showthread.php?t=103334 I can send you pics of the heads later if you would like. PM me...
The cam I used was a mild XE262.

 

[rgtrough]

Hey minifridge, I am thrilled with my AFR 195 eliminators. They flowed great right out of the box.(277 intake) I see no reason why the 180s would not have just as high quality. I am curious about you compression ratio. Do you have domed pistons?
Bud

 

[Curtis]

check this out....http://www.superchevy.com/technical...etebuilds_testing/0312sc_dm15_copy/index.html ...... now you can get even better vortec heads than was used in this test.. incidentally, AFR heads are spendy and develope less power than the vortecs as tested. i run the vortecs and have no regrets... 87 octane fuel is just fine. i do have the XE 268 cam which gives up a few pounds of torque, but makes about 15 more horsepower on top. my motor will keep you pasted in your seat from 1500 to 5500 rpm. works for me. !!!!!

 

[Hib Halverson]

Even if there is a Vortec head that out performs the AFR, it won't be by much and, the weight you take off the front end by going to the aluminum heads will probably be the equalizer.

I'd say that the AFRs with that cam and compression ratio will be killer as long as you use a Performer RPM intake and a Quadrajet.

 

[Crimson Thunder]

That article compares Vortec heads against TFS heads not AFR heads.

 

[Curtis]

Yes, I know that portion of the testing was with TFS.. AFR was also tested. I just intended to show what was possible on the low cost side as far as heads. I thought it was good information since many of us can't afford aluminum or premium gas.

 

[Vette79]

Here's a comparison between Vortec and AFR Heads. http://www.popularhotrodding.com/en...re/0405em_chevy_small_block_engine/index.html

 

[minifridge1138]

I was trying to shy away from vortec heads. I do not believe my hooker competition headers will bolt to vortec heads, so I wanted to keep the stock plug/exhaust manifold pattern.

The compression ratio of 10.55 to one is just an estimate based on a software dyno (We all know how reliable they are).

Another 'upgrade' i was considering was going to roller lifters instead of flat tappet.

As I said before, my car is still running strong. I am just trying to put together a shopping list so that I can buy parts slowly over time and drive the car in the mean time.

 

[glen242]

Hey everyone,

My engine is 26 years old and is showing some signs of age. I'm not going to start tearing it apart in the immediate future, but I am trying to put together a shopping list of things i'm considering.

Does anyone have any experience with AFR Cylinder heads? I have been looking at their 180cc. The combustion chamber is 75cc which (if my math is correct) would put my compression ration at about 10.55:1 (depending on head gasket thickness.

In terms of a cam I have been looking at a comp cam part with the following stats:
Intake Exhaust
Duration (0.05 inch) 212.0 218.0
Duration (seat to seat) 256.0 268.0
Valve Lift (std rocker) 0.447 0.454
RPM Range of 1000-5200

I'm not trying to build a race car. But if i'm already going to the trouble of taking the engine apart I would like to get more power but keep pump gas.

Thoughts, comments, and crude remarks are welcome!!!

I don't believe your static CR will be 10.55 regardless of what gasket you use. 1982 specs show using sump (dish) pistons. Along with 76cc heads, stock CR was luckly to be 8.5.

Re do your CR math using the correct numbers.

http://www.kb-silvolite.com/calc.php?action=comp

 

[rgtrough]

Hey Mini, yeah your CR is probably lower than that estimate. The beauty of the roller lifter/cam swaps are the steeper grinds that are possible with them. Don't forget the exhaust side of the heads. You will probably want some larger headers to let those 180's
breathe. Let the technical departments of the various manufacturers suggest combos for you.
peace Bud

 

[Glensgages]

I don't believe your static CR will be 10.55 regardless of what gasket you use. 1982 specs show using sump (dish) pistons. Along with 76cc heads, stock CR was luckly to be 8.5.

That caught my-eye, too..... I believe the 'shown' CR on the L83/Cross-Fire is 9.2:1 w/ 76cc heads:
when I ran the numbers using an L83 short-block, I recall getting about 10.3 w/ 64cc heads, and 10.9 w/ 58cc ZZ4/L98 heads, 'if' the 9.2:1 figure is correct.