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Heads and cam.....here we go again

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Old 09-15-2018, 11:19 AM
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Capt. Shark
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Default Heads and cam.....here we go again

Every time I talk myself out of what I really want to do, I am sorry later. My 79 L82 engine came out two winters ago and was stripped to bare block, everything reconditioned and all the stock lower end parts went back. I used Dart 165/72cc iron heads shaved down just a little for 9.5 CR and a COMP XE268 flat tappet cam.
Edelbrock Performer and Lars tuned Q-Jet. Ignition is all new stuff and timing is set up correctly. Sanderson shorties and true duals. At the time I wanted to go with aluminum heads and a roller cam but talked myself out of it. Made a big difference from before but here I am........

Now my upcoming winter project is either AFR or Profiler 185/64cc aluminum heads and one of these three cams.
COMP XR276HR https://www.summitracing.com/parts/c...make/chevrolet
Lunati Voodoo 20120711 https://www.summitracing.com/parts/lun-20120711lk
Howards 110245 https://www.howardscams.com/hydrauli...cams-110245-12

All three are similar specs, I am leaning towards COMP but only because I have never used Lunati or Howards.

Should have added it's a 4 speed and 3.70 rear end.

Of those three what do you guys like? Or something else?

I'm looking for just a little more go.

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Old 09-15-2018, 01:31 PM
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Originally Posted by Capt. Shark View Post
Every time I talk myself out of what I really want to do, I am sorry later. My 79 L82 engine came out two winters ago and was stripped to bare block, everything reconditioned and all the stock lower end parts went back. I used Dart 165/72cc iron heads shaved down just a little for 9.5 CR and a COMP XE268 flat tappet cam.
Edelbrock Performer and Lars tuned Q-Jet. Ignition is all new stuff and timing is set up correctly. Sanderson shorties and true duals. At the time I wanted to go with aluminum heads and a roller cam but talked myself out of it. Made a big difference from before but here I am........

Now my upcoming winter project is either AFR or Profiler 185/64cc aluminum heads and one of these three cams.
COMP XR276HR https://www.summitracing.com/parts/c...make/chevrolet
Lunati Voodoo 20120711 https://www.summitracing.com/parts/lun-20120711lk
Howards 110245 https://www.howardscams.com/hydrauli...cams-110245-12

All three are similar specs, I am leaning towards COMP but only because I have never used Lunati or Howards.

Should have added it's a 4 speed and 3.70 rear end.

Of those three what do you guys like? Or something else?

I'm looking for just a little more go.
I would get rid of the Sanderson "headers" and Performer intake first. They are choking it to death and its only gonna be worse with better heads and a bigger cam.

Pick out your heads first, then select a cam based on the heads/compression. All of those three rollers are about the same size cam you have now so....I wouldn't expect a HUGE gain...maybe 10-15hp... I'd probably go with the AFR 180 heads, RPM air gap intake, and a Comp 230/236* hyd roller.... something in that ball park. With real headers. Should make 400hp+ pretty easy if you can get the compression up with smaller cc chambers.

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Old 09-15-2018, 01:33 PM
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Get a custom cam made....
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Old 09-15-2018, 01:54 PM
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Whatever you can do wiht the cam to help pack that cylinder more, as said a better dual plane will help.
What rpm are you thinking of max? Any of those will make for a pretty good running 350. Ought to be able to hit high 3xx if not 400 at the crank with excellent torque.

Anyone know if those TFS 175 double humps come in a 58cc chamber? That would pick his CR up some he can afford it with a better head

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Old 09-15-2018, 02:42 PM
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I have done what you are looking to do with my 78 L-82 4 speed with 3.70 gears back in 2014.

I decided to completely rebuild the OEM L-82 with as many of the L-82 good components as possible and wanted to retain as much L-82 looking engine as was reasonable right down to the OEm L-82 dual snorkel cold air intake.

i worked with a local engine builder/high performance tuner (GM only in my area - we remain good friends to this day and I periodically stop in to BS with him) as to the best parts combo to give my the most streetable gross HP/Torque from the L-82 355 without going to a 383 which I did not want to do. Here is what we did after I pulled the L-82 in my garage and the builder picked up the short block from my house:

The L-82 block was bored .030 to a 355. The block was NOT decked since it was straight and no need for a street engine of 425-450+ Gross HP. The L-82 forged crank was reconditioned , reconditioned the L-82 forged rods, ARP bolts, and JE forged racing pistons (9:1). The builder built the bottom end of the motor and delivered it to my house for the top end build by me and the reinstall.

Since I was looking to get maximum power on the street and was looking for BIG mid range torque for the 355 with the 3.70 gears and 4 speed I selected AFR 180 64 CC heads which are pretty much the best out of the box CNC heads you can buy (yes there are others that are close if you choose to spend less money). The heads were checked by my builder before install and were perfect...no modifications needed. I used a felpro .015 head head gasket for a final compression ratio of 10.2:1. The engine runs with zero detonation on 89 octane fuel with ethanol in it to boot.

I did use a howards retro roller cam-219/225 duration, LSA 110, .525/.525 lift, operating range 1,500-5,600 RPM

https://www.howardscams.com/hydrauli...0-howards-cams

I strongly recommend you look carefully at this cam. I just drove the car today and the motor has very strong bottom end, BIG mid range torque, and pulls hard to 6,000 RPM. I rarely rev past 5,700-5,800 much on the street and have no need to since the engine pulls VERY HARD from 2,500-6,000 RPM. I have zero interest in a 383 after building my 355 with these components. My engine feels stronger than most 383's with the carefully selected optimum components to work with the 3.70 gears/4 speed. You want a lower duration cam with a tight LSA (110) with as much lift as possible to work with the duration. The cams you are looking at with 230's+ duration are great for top end power but you want strong mid range power on the street with very good high RPM HP (219/225) which is where the engine lives 90% of the time. Your lift should be at least .525+ if you go with the AFRs.

I reused the L-82 intake that was slightly ported on the expert advice of my builder who also races drag cars of his own. His advice was under 6,000 RPM the L-82 intake is pretty good and for street driving don't bother chasing 5-7 HP with aftermarket intakes unless you are going over 6,500 RPM. He was spot on since my engine pulls hard right to 6K, no out of breathe anywhere in the higher RPM's. You can keep the performer or switch to a performer RPM for 5 HP extra if you want to spend the money.

Exhaust-I drove this engine with mcjacks shorty headers from the OEM L-82 for the first 3 years and it performed VERY strong with these shorty's. 2 years ago I switched to 1 3/4 inch XS power LTH headers and yes the engine does pull stronger at RPM's above 4,000 RPM but it is NOT an OMG moment..not even close.

Hope this helps you^^^^^^^^^.

BTW-I would guess you current compression ratio if you are using the stock L-82 pistons (advertised ratio was 8.9:1, if you are lucky) with a 72 CC head is probably at best 9.2:1 maybe.....

You can PM me if you want more details

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Old 09-15-2018, 04:59 PM
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Of the ones you listed I would go with the Lunati cam. A 109 LSA would be more fun vs 110 or 112. Get as much lift as you can. Put 1.6 rr on it and you get right at .549 llift on the intake. The AFR heads do not need a split on the intake to exhaust duration. So something with minimal to no split is going to be better for those heads. Although you could run 1.6 on the intake and 1.5 on the exhaust to make the Lunati closer to no split cam spec.

I run a 270/270 with .549 lift on a 108 LSA and it is super snappy with noticeable idle. Runs right up to 6300 rpm at which point the AFR 180 cc head springs start to float.

I would say long tube headers would really complement the combo. I run side pipes myself.

also run the performer intake, but has been ported and opened up to accommodate the flow of the heads.

keep in mind that going to a roller is like adding 15 degrees or so duration. The roller cam offers better vacuum though. I get around 14” at 800 rpm with my cam.

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Old 09-16-2018, 11:49 AM
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There is only a couple of things for me to add....
I'd stay away from the comp XR276HR or any other comp cam in that series. The valve train noise will drive you nuts, it sounds exactly like a solid lift cam. These cams are well know for this noise, and I only wish I had listened to others before putting that very cam in my engine.

If you go with the AFR heads, You don't need a huge cam to make great power, stay on the milder side and you will be rewarded with great power in the 6000 and under RPM range. As jb78-L82 says using the 1.6 rockers to get valve lift up into the mid .500" will really help take advantage of the flow capabilities of the AFR heads.

I'd ditch the performer intake and get a performer RPM.....and gasket match the intake to the heads
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Old 09-16-2018, 12:01 PM
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I like the Howards grind......but forget the whole thing unless you run a pair of long tube headers.

Jebby
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Old 09-16-2018, 12:59 PM
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Thanks for all the responses. I should probably just leave it alone, it runs great. I'm not sure throwing another two or three thousand dollars at it would be worth the small gain in performance.
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Old 09-16-2018, 01:35 PM
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stocker same opinion here. couple of those went flat right away, even an XFI roller at 18k.
If you use a steep ramp cam I would not use 1.6 unless you spring it accordingly. For me the valvetrain getting hammered is not worth a few lbs in torque and reduced life.
Others like them.

If op does H/C he will definitely feel it guess it depends on his expectations per dollar spent.
I was never happy til I added more stroke and lots of H/C. Its never enough

op you can always leave it as is....save up for something like a mild blueprint 400? Cubes are where its at!

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Old 09-16-2018, 02:07 PM
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Originally Posted by Capt. Shark View Post
Thanks for all the responses. I should probably just leave it alone, it runs great. I'm not sure throwing another two or three thousand dollars at it would be worth the small gain in performance.
I would say the chances of your XE268 getting a flat lobe in the future are 50-50.

Right now you're at about 350HP ish range.

Given either jb78l82's or my combo you'd be around 425HP or greater. For me it was a no brainer on the roller vs the flat tappet cam. The roller offers so many advantages over the flat tappet not to mention peace of mind and the flexibility to run whatever oil I deem appropriate without having to worry about zinc content.

I know how it can be a tough descision to tear apart a perfectly good engine to potentially achieve better results when what you got is good enough. Done it twice now, but have not regretted either time. Each time it just gets better and you end up learning more.
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Old 09-16-2018, 08:42 PM
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I am running a '70 355 with the Howard's 110245 retro roller and dart SHP's, long tube headers and a weiand dual plane intake. Compression 9.7. I'm very happy with the combo, but at times wish I had a bit more low end torque (see jb78's combo with slightly less duration) but more lift. Mine is done at 5800, and I think the intake is probably stifling it a bit and I wish I'd gone a bit more on the lift, so maybe next time around... I wanted the stock hood and air cleaner on my L46 so chose this intake. Also wish I'd gone AFR as the Darts presented some pushrods alignment issues on the intakes when I originally assembled the top end.

i am also running a wide ratio 4-sped and 3.73 rear gear.

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Old 09-17-2018, 07:05 AM
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Originally Posted by JoeMinnesota View Post
I am running a '70 355 with the Howard's 110245 retro roller and dart SHP's, long tube headers and a weiand dual plane intake. Compression 9.7. I'm very happy with the combo, but at times wish I had a bit more low end torque (see jb78's combo with slightly less duration) but more lift. Mine is done at 5800, and I think the intake is probably stifling it a bit and I wish I'd gone a bit more on the lift, so maybe next time around... I wanted the stock hood and air cleaner on my L46 so chose this intake. Also wish I'd gone AFR as the Darts presented some pushrods alignment issues on the intakes when I originally assembled the top end.

i am also running a wide ratio 4-sped and 3.73 rear gear.




That's exactly correct Joe^^^^. The Howards cam you have with 225/231 duration is a bit high for a street 355 even with a 4 speed and 3.70 gears if you want to be in the sweet Torque range for 90% of your driving. The 219/225 duration for my howards roller is well suited for strong bottom end and big mid range torque (LSA 110, 2,500-4,500 RPM) especially with a 4 speed. AFR's are very well suited to split duration cams of 4-6 degrees as well as cams with no split duration. I think a 383 with its slight torque advantage (15-20 ftlbs) at about 4-500 lower RPM is probably better suited to an automatic. And yes, I probably would have gone higher with lift than .525/.525 from howards if they had a lower duration combo with say .550 lift but they did not. I selected my roller as well since it had a broad operating range, 1,500-5,600 RPM. I was strongly advised to keep the duration lower with my roller cam and the AFR 180's. I think the tendency is for many folks to go too big on duration for street engines. My Restraint on this front paid off in spades......

I do believe the secret to making very strong power from a street 355 is the CNC AFR 180's which pretty much flow the best of any bolt in heads not so much at peak lift but across the lift spectrum, low and mid lift. They simply make great power from off idle to redline. I really went AFR's on the strong recommendation from my builder who knew what I was after in the build. He also said my split duration cam would work fabulously with my combo...he was spot on....

Another .5 point in compression to 10.2-3:1 would also give you some more power. I am very happy with my ported OEM aluminum L-82 intake which is not restrictive at all sub 6,000 RPM as predicted and advised by my builder to retain.

Getting the max power from a street 355 is all about the right/best components with a tweak here and there...................to make it all come together.

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Old 09-17-2018, 08:13 AM
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Originally Posted by Capt. Shark View Post
Thanks for all the responses. I should probably just leave it alone, it runs great. I'm not sure throwing another two or three thousand dollars at it would be worth the small gain in performance.
This is what I was thinking.
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Old 09-17-2018, 09:24 AM
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Originally Posted by stingr69 View Post
This is what I was thinking.
Maybe I should put that money towards a TKO 5 speed
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Old 09-17-2018, 09:36 AM
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Originally Posted by Capt. Shark View Post
Maybe I should put that money towards a TKO 5 speed
Now I REALLY like your thinking.
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Old 09-17-2018, 10:22 AM
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Originally Posted by Capt. Shark View Post
Maybe I should put that money towards a TKO 5 speed
NOW YOUR TALKING...That's the best mod I ever made to my car....
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Old 09-17-2018, 12:20 PM
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Heck yeah you will never say "I shouldnt of"... who cares whats a tenth quicker its about fun.
Theres perfect 10s out there that boring. Sorta. Unless you pay em thats different.
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Old 09-17-2018, 12:53 PM
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Originally Posted by sstocker31 View Post
NOW YOUR TALKING...That's the best mod I ever made to my car....


Originally Posted by cuisinartvette View Post
Heck yeah you will never say "I shouldnt of"... who cares whats a tenth quicker its about fun.
Theres perfect 10s out there that boring. Sorta. Unless you pay em thats different.
I can't afford that.........either one
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