Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comments

[William H.]

Hello everyone,
Per Comp Cams Help Line I am looking at Cam 12-430-8 Hydraulic Roller Lifter Cam:

224 durations at .050"
280 Advertised
.525/.525 Lift
110 Degree LSA
2000-6000 powerband
Running stock L2166nf-.030 pistons
Factory intake Carburetor and Exhaust Manifolds Currently factory side pipes but may switch to N11 undercar exhaust.
1965 Coupe PW, Tele, PB, PS and A/C
3.73:1 rear gear 2.20:1 Low M21
Any Comments or suggestions would be appreciated greatly.
Thanks in advance and Bless you all.
Bill

[Joe L.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Hello everyone,
Per Comp Cams Help Line I am looking at Cam 12-430-8 Hydraulic Roller Lifter Cam:

224 durations at .050"
280 Advertised
.525/.525 Lift
110 Degree LSA
2000-6000 powerband
Running stock L2166nf-.030 pistons
Factory intake Carburetor and Exhaust Manifolds Currently factory side pipes but may switch to N11 undercar exhaust.
1965 Coupe PW, Tele, PB, PS and A/C
3.73:1 rear gear 2.20:1 Low M21
Any Comments or suggestions would be appreciated greatly.
Thanks in advance and Bless you all.
Bill

Bill------


I think this would be a very good cam for your application.

Incidentally, in case you are not aware, since you require a RETROFIT hydraulic roller, there is no GM-sourced camshaft, lifters or kit available, now or ever in the past.

[William H.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Thanks Joe!

[Peter G.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Hello everyone,
Per Comp Cams Help Line I am looking at Cam 12-430-8 Hydraulic Roller Lifter Cam:

224 durations at .050"
280 Advertised
.525/.525 Lift
110 Degree LSA
2000-6000 powerband
Running stock L2166nf-.030 pistons
Factory intake Carburetor and Exhaust Manifolds Currently factory side pipes but may switch to N11 undercar exhaust.
1965 Coupe PW, Tele, PB, PS and A/C
3.73:1 rear gear 2.20:1 Low M21
Any Comments or suggestions would be appreciated greatly.
Thanks in advance and Bless you all.
Bill

I have a few comments.
That cam is really big for factory exhaust manifolds and your factory cylinder heads.

You better purchase a complete valve spring kit that is designed for this high lift. You don't want the springs to bind when compressed at full lift.

The Lobe Separation Angle for this cam will produce good power at the top end, but you pay the price with low vacuum. I would guess this cam would produce about 12 inches of vacuum at idle. As a result, your power brakes will not respond as they did with a factory cam.

Roller cams with their kits are rather expensive. You might be better off finding a high lift hydraulic cam with about .480 inch lift max for your cylinder heads. Duration at .050" around 218. If you want your power brakes to feel like they were installed at the factory, you need a lobe separation angle (LSA) of at least 116 degrees. This profile will give you a nice idle with good vacuum 18"-20".

Otherwise with a 110 lobe separation angle, you will develop less vacuum at idle, have a moderately rough idle, and your power brakes will feel dramatically different, as they are vacuum boosted.

You can do what you want, but I personally think that roller cam is way too big for your car.

[Leif A.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

I have a few comments.
That cam is really big for factory exhaust manifolds and your factory cylinder heads.

You better purchase a complete valve spring kit that is designed for this high lift. You don't want the springs to bind when compressed at full lift.

The Lobe Separation Angle for this cam will produce good power at the top end, but you pay the price with low vacuum. I would guess this cam would produce about 12 inches of vacuum at idle. As a result, your power brakes will not respond as they did with a factory cam.

Roller cams with their kits are rather expensive. You might be better off finding a high lift hydraulic cam with about .480 inch lift max for your cylinder heads. Duration at .050" around 218. If you want your power brakes to feel like they were installed at the factory, you need a lobe separation angle (LSA) of at least 116 degrees. This profile will give you a nice idle with good vacuum 18"-20".

Otherwise with a 110 lobe separation angle, you will develop less vacuum at idle, have a moderately rough idle, and your power brakes will feel dramatically different, as they are vacuum boosted.

You can do what you want, but I personally think that roller cam is way too big for your car.

As a comparison to the roller cam that the OP was originally talking about and to what Pete has referenced...the attached sheet is the cam I chose four years ago when I had to replace my OE L79 cam because of a lifter failure. Cam delivers great performance. Idles at 750RPM with 15" steady vacuum. Just some additional information for the OP to consider.

[Joe L.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

I have a few comments.
That cam is really big for factory exhaust manifolds and your factory cylinder heads.

You better purchase a complete valve spring kit that is designed for this high lift. You don't want the springs to bind when compressed at full lift.

The Lobe Separation Angle for this cam will produce good power at the top end, but you pay the price with low vacuum. I would guess this cam would produce about 12 inches of vacuum at idle. As a result, your power brakes will not respond as they did with a factory cam.

Roller cams with their kits are rather expensive. You might be better off finding a high lift hydraulic cam with about .480 inch lift max for your cylinder heads. Duration at .050" around 218. If you want your power brakes to feel like they were installed at the factory, you need a lobe separation angle (LSA) of at least 116 degrees. This profile will give you a nice idle with good vacuum 18"-20".

Also, it must be kept in mind that specifications for hydraulic roller cams cannot be directly compared with flat tappet cams.

Otherwise with a 110 lobe separation angle, you will develop less vacuum at idle, have a moderately rough idle, and your power brakes will feel dramatically different, as they are vacuum boosted.

You can do what you want, but I personally think that roller cam is way too big for your car.

Pete------


I do not recommend a flat tappet cam and lifters under any circumstances. I would NEVER install such a cam in any engine I built. The results of one "wiped out" cam and lifters will pay for a lot of retrofit hydraulic roller kits. I've heard of too many such results when flat tappet cams are used in the modern world.

I think the cam described will provide performance pretty much consistent with the original L-79 cam. If Bill wants to "hedge his bets" a little, he might go with a 12-420-8. I don't think that vacuum will be a problem. Some stock SHP Chevrolet cams produced idle vacuum on the low side and were also equipped with power brakes that worked just fine.

Also, it must be kept in mind that specifications and/or performance characteristics for hydraulic roller cams cannot be directly compared with flat tappet cams.

[Steven B.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Hello everyone,
Per Comp Cams Help Line I am looking at Cam 12-430-8 Hydraulic Roller Lifter Cam:

224 durations at .050"
280 Advertised
.525/.525 Lift
110 Degree LSA
2000-6000 powerband
Running stock L2166nf-.030 pistons
Factory intake Carburetor and Exhaust Manifolds Currently factory side pipes but may switch to N11 undercar exhaust.
1965 Coupe PW, Tele, PB, PS and A/C
3.73:1 rear gear 2.20:1 Low M21
Any Comments or suggestions would be appreciated greatly.
Thanks in advance and Bless you all.
Bill

Small point but if factory gearing '65 was 3.70 as 3 73's came later. Sounds like nice car!

[Duke W.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

The last place I would go for "cam advice" is the Comp Cams "help line". IMO the LSA on this cam is too narrow. The L-79 cam is 114 degrees. The lower the LSA (for a given duration) the more overlap, and the more overlap the rougher the idle and the lower the manifold vacuum, the minimum acceptable stable idle speed, and the lower the low end torque/power.

Idle vacuum is not an issue with power brakes because every time you lift off the throttle there is a vacuum spike that evacuates the PB booster. It may be an issue on C3s since they have more vacuum systems. Power brakes were available with the 30-30 cam engines and in my experience about the lowest they will idle with acceptable quality is 900 and at that idle speed they only pull about 10" Hg manifold vacuum, and any cam that idles lower than 10" does not belong in a road engine!

For years I've recommended the L-46/82 cam (224/224/114/114/114/.300/.306" lobe lift), installed four degrees advanced on 327s, to bring the IPOML back to equal the L-79 cam, so the POMLs/LSA become 110/118/114. The L-46/82 cam was designed after Chevrolet learned a lot about lobe dynamics with the Optron studies. It has softer lobe dynamics.

There are a couple of issues with flat tappet cams. First is that ALL grinders that offer GM spec cams call out MUCH STIFFER than OE springs? Why? I don't know, but I DO KNOW that properly set up OE 3911068 (Sealed Power VS-677) valve springs will not pump up until at least 6500 with an OE equivalent hydraulic lifter cam, but you need to massage the heads to make usable power this high with the L-79 or L-46/82 cams.

If you do install a GM equivalent cam WITH GM equivalent valve springs (about 80 pounds on the seat and 200 open) and do the usual "cam break-in - 20-25 minutes revving at about 2500 using C-category engine oil with a ZDDP supplement (for break-in only) - very likely the cam will live.

The wild card is the cam blank and lifters. Various reports - anecdotal - that cams and/or lifters are "soft" have been out there for years. Who knows? But ask the manufacturer (not a retailer like Summit) questions about lobe and lifter hardness, and always ask for the cam to be Parkerized (which aids break-in) , even if it adds cost.

AFAIK all flat tappet cam blanks for both big and small blocks are made by the CWC division of Textron. There are literally DOZENS if not hundreds of flat tappet grinds available for small blocks and they are ALL ground on the same CWC blank. How about that!

https://www.kautex.com/en/mobility/cwc-textron-castings

So ask the cam grinder about where he gets his blanks and his experience with them. Like I said ALWAYS deal directly with the grinder, not some retailer who likely doesn't know jack... they just want your order. Also ask who is their lifter source and quality experience with them.

Likely the two best sources for OE cam grinds are Elgin in Santa Rosa CA and Howard's Cams in Oshkosh WI. They have lobe masters for virtually all OE cams, and they can also grind the McCagh Special camshaft.

Just IGNORE their valve spring recommendations, and use OE equivalent valve springs.

Duke

[Patrick B.]

[Mark E.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Every so often the Duke/flat tappet versus Joe/roller cam debate resurfaces. Always entertaining to read.

[Gary B.]

[William H.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Hello All,
I forgot to mention one important point!
I am strongly considering Running Trick Flow Aluminum Double-hump Head Copies. Think they are good for the .525 lift the cam I am looking at has. Does this make any Difference to anyone's opinion?
Thanks again,
Bill

[Duke W.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Duke— You are so right. I bought an Elgin LT1 cam that looked nice and was parkerized, but they listed heavy springs in the kit. Elgin actually makes springs with the same nominal spec as the stock Chevy springs, but they may not be listed in the Competition Products Catalog. I think the number is 8080, and I found mine on EBay. If you can talk to someone at Elgin that would be best.

The 3911068 specs are as follows:

80 lb. @ 1.70" compressed height
267 lb./inch rate that yield an open force close to 200 lb. depending on the OE cam
Coil bind height 1.15"

It's a single spring with an internal flat wire damper.

These were used on most small blocks (including ALL Corvette SHP engines like L-79, L-46/82 and LT-1) from '67 to at least 79, so millions of these were produced, and I find it incomprehensible that they are no longer available from Tier 1 sources Like the former Federal Mogul that is now owned by Tennaco.

I doubt if Elgin winds their own springs, and it would be nice to know the source

Duke

[Duke W.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

Every so often the Duke/flat tappet versus Joe/roller cam debate resurfaces. Always entertaining to read.

Joe and I are on the same page on just about everything, but this is one area where we differ. I'd rather spend the money on bullet proof connecting rods and head massaging or aftermarket heads that flow at least 220/170 CFM @ 28" H2O depression, valve lift in the range of .400-.450". Flow at higher lifts is meaningless for OE cams since the maximum rocker ratio at 1.44:1 is less than GM's claimed 1.5:1.

Do it right with a LT-1 cam and you can buzz a 327 to 7000 as often as you like and 6500 with the L-79 or L-46 cam.

Duke

[Peter G.]

Re: Comp Cams HYD Roller for 65 327/350HP with PB, A/C and 3.73:1 rear gear. Any Comm

As a comparison to the roller cam that the OP was originally talking about and to what Pete has referenced...the attached sheet is the cam I chose four years ago when I had to replace my OE L79 cam because of a lifter failure. Cam delivers great performance. Idles at 750RPM with 15" steady vacuum. Just some additional information for the OP to consider.

That Comp Cam is a nice cam. If you are running 2.02" intake valves and 1.6" exhaust valves, it works great. But I still like a Lobe Separation Angle of 114 to 116 degrees for street use. You could even use 1.6 rocker arms in place of the factory 1.5 to boost the lift just a bit more and it would add a couple of degrees to the cam.

The intake and exhaust port volumes on these L79 style heads with 1.94" intake valves and 1.5" exhaust valves are limited and do not allow as much air flow as let's say the 1992-1996 LT1 heads which use a hydraulic roller cam. So you always have to keep that in mind when choosing a replacement cam.

I prefer Isky, Crower, and Comp Cams.

As someone else mentioned in this post, don't forget about the bottom end. You can't do high RPM's with reliability with a cast crank and pistons. So this spec cam should be more than what you need for street use.