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Thu Aug 28, 2025 11:43 am

Hi All,

I need your help in selecting a cam that isn't hard on lifter bores and that won't stop pulling over 6500 rpm. I'm looking for a cam to improve mid to up range of the RPM band. Any thoughts?

Here are my current engine specs:

2165cc
L6 DRD heads (42mm x 37mm)
SLR R302 cam, similar to the FK-8
1 5/8 A1 exhaust system
Dual 44s Weber with 38mm chokes
9:1 compression.

Thanks

Thu Aug 28, 2025 1:09 pm

I would look into the heads, and make sure the seat/valve ratio is correct. Lots of those DRD heads had a 42mm valve stuck on a 44mm seat. No bottom cuts, and a terrible ratio.

Get the heads right, then swap to a Web 86c, bump to 10.5:1. It might need 48's and a bigger header after that.

Brian

Thu Aug 28, 2025 1:50 pm

VW&MGman wrote: Hi All,

I need your help in selecting a cam that isn't hard on lifter bores and that won't stop pulling over 6500 rpm. I'm looking for a cam to improve mid to up range of the RPM band. Any thoughts?

Here are my current engine specs:

2165cc
L6 DRD heads (42mm x 37mm)
SLR R302 cam, similar to the FK-8
1 5/8 A1 exhaust system
Dual 44s Weber with 38mm chokes
9:1 compression.

You can make it rev high, but it wohnt make power. Those heads are terrible. your best bet is to get the valves/seats corrected. If you are not up to that I would chose a cam which makes very good vacum. XR310 on 106 LC advanced 2 degrees., CB 2289 on 104-105 ILC. or something like that.

Thanks

Thu Aug 28, 2025 4:32 pm

Brian_e wrote: I would look into the heads, and make sure the seat/valve ratio is correct. Lots of those DRD heads had a 42mm valve stuck on a 44mm seat. No bottom cuts, and a terrible ratio.

Get the heads right, then swap to a Web 86c, bump to 10.5:1. It might need 48's and a bigger header after that.

Brian

Feel like this is a dumb question as ive gotta be missing something here, but how the hell do you use a 42mm valve on a 44mm seat?

Thu Aug 28, 2025 5:00 pm

BFB wrote: Brian_e wrote: I would look into the heads, and make sure the seat/valve ratio is correct. Lots of those DRD heads had a 42mm valve stuck on a 44mm seat. No bottom cuts, and a terrible ratio.

Get the heads right, then swap to a Web 86c, bump to 10.5:1. It might need 48's and a bigger header after that.

Brian

Feel like this is a dumb question as ive gotta be missing something here, but how the hell do you use a 42mm valve on a 44mm seat?

Ha. CB and others have been doing it for years. They use the same seat insert for both sizes of valves. They are correct for the 44mm, but the 42 rides way out at the edge of the valve, and there is no room for the bottom cuts because the material isn't there, and the ratios are all wrong.

These are pics of a CB mini wedgeport with a 42mm valve straight from CB. The seat/valve ratio was 92%, and they flowed 178CFM @ .550".

All I did was re-cut the same seat to be properly placed on a 44mm valve. I DID NOT REPLACE THE SEAT.... This corrected the seat/valve ratio, and it got the I/E ratio back down to 77% where it should be. After the seat cut they flowed 204 @ .550". That was a 26cfm gain, corrected the I/E ratio, corrected the seat/throat ratio, made a MASSIVE increase in airspeed, and made no increase in the port volume. 42x37.5's are a screwy size, and they need to be done carefully to work right. Most heads are just done production style to get them out the door. Sharing the same seat size is easy for them, and 90% of the people buying them hardly know any better....

Brian

Thu Aug 28, 2025 6:08 pm

Wow, talk about doing something half-assed like using 42mm valve on a 44mm seat !

The cost diff to use the correct seat/valve has to be peanuts. Maybe save a few pennies by not cutting the seats for optimal flow and airspeed.

Thats crazy and thx for the heads up :thumbsup:

Thu Aug 28, 2025 8:46 pm

I think they do it mostly so they only need the 2 part numbers to keep in stock. The one seat covers the 42 and 44mm, and then another part number for the 40mm.
Then when they are ordered, they just cut the seats for either the 42, or the 44, and send it out the door.

I am hoping to get a pair of new EMPI stage 3’s from a guy to test, and I am betting they are the same way.

Brian

Fri Aug 29, 2025 6:53 am

Brian_e wrote: BFB wrote: Brian_e wrote: I would look into the heads, and make sure the seat/valve ratio is correct. Lots of those DRD heads had a 42mm valve stuck on a 44mm seat. No bottom cuts, and a terrible ratio.

Get the heads right, then swap to a Web 86c, bump to 10.5:1. It might need 48's and a bigger header after that.

Brian

Feel like this is a dumb question as ive gotta be missing something here, but how the hell do you use a 42mm valve on a 44mm seat?

Ha. CB and others have been doing it for years. They use the same seat insert for both sizes of valves. They are correct for the 44mm, but the 42 rides way out at the edge of the valve, and there is no room for the bottom cuts because the material isn't there, and the ratios are all wrong.

These are pics of a CB mini wedgeport with a 42mm valve straight from CB. The seat/valve ratio was 92%, and they flowed 178CFM @ .550".

All I did was re-cut the same seat to be properly placed on a 44mm valve. I DID NOT REPLACE THE SEAT.... This corrected the seat/valve ratio, and it got the I/E ratio back down to 77% where it should be. After the seat cut they flowed 204 @ .550". That was a 26cfm gain, corrected the I/E ratio, corrected the seat/throat ratio, made a MASSIVE increase in airspeed, and made no increase in the port volume. 42x37.5's are a screwy size, and they need to be done carefully to work right. Most heads are just done production style to get them out the door. Sharing the same seat size is easy for them, and 90% of the people buying them hardly know any better....

Brian

so your saying you used a 44 instead of the 42 on this?

Fri Aug 29, 2025 8:16 am

They were ordered as 42mm CB mini wedgeport heads. I threw the 42mm valves aside, and I re-cut the existing seat in the head to correctly fit a new 44mm valve. No other changes. Same seat insert ring, same springs, same chamber shape. Instant 26cfm gain, and MUCH better flow through the entire lift curve.

Its all about ratios, correctly placing the seat on the valve face, and setting up the air so it can make it past the valve as efficiently as possible.

Brian

Wed Sep 03, 2025 10:17 pm

Don't give the CB Performance 2242 cam a miss

Fri Sep 05, 2025 5:01 am

TheRookie wrote: Don't give the CB Performance 2242 cam a miss I have this cam and its a good cam. I wouldn't want anything more if it were a daily driver.

Fri Sep 05, 2025 9:27 am

WaterBuggy_24 wrote: TheRookie wrote: Don't give the CB Performance 2242 cam a miss I have this cam and its a good cam. I wouldn't want anything more if it were a daily driver.

He has a cam that is near 258deg. and he is looking for more top end. Changing to a cam with 10deg. LESS duration is only going to LOOSE top end.

Brian

Fri Sep 05, 2025 10:26 am

Thanks all for your input.

I'm considering CB's 2246 cam which has the following specs:

Dur. @ .050" 260°
Lift @ cam .411"

I called CB and unfortunately they weren't able to say what the expected power band would be for this cam.

Does anyone run this cam and what your thoughts?

My other thought is to retard my current cam by 2 degrees as it is currently installed dot to dot. Any thought on this?

Fri Sep 05, 2025 10:28 am

as others have mentioned, take a close look at your heads...and consider better ones. The cam will not fix heads that can't perform like they could.

Fri Sep 05, 2025 11:02 am

VW&MGman wrote: Thanks all for your input.

I'm considering CB's 2246 cam which has the following specs:

Dur. @ .050" 260°
Lift @ cam .411"

I called CB and unfortunately they weren't able to say what the expected power band would be for this cam.

Does anyone run this cam and what your thoughts?

My other thought is to retard my current cam by 2 degrees as it is currently installed dot to dot. Any thought on this?

Adding 2 degs duration, and less lift will gain you almost nothing. If your current cam is a 1.4 rocker cam, like the FK8, the cb2246 will most likely be less RPM power with only .450" lift and 1.1 rockers.

I still vote for a web 86c, but the heads need to be corrected before ANY cam will make much improvement.

Brian

Fri Sep 05, 2025 11:09 am

I´ll say this once more and then never again. If you want power you need to correct those heads, or go aggressive on the cam, like FK10 or FK87 and accept very little usable power below 3500 bbut it will pull decent up to about 7400
you can also go Web 121/125 and get a decent powerband.
But the right way is to correct those intakes.

Fri Sep 05, 2025 3:11 pm

Alstrup wrote: I´ll say this once more and then never again. If you want power you need to correct those heads, or go aggressive on the cam, like FK10 or FK87 and accept very little usable power below 3500 bbut it will pull decent up to about 7400
you can also go Web 121/125 and get a decent powerband.
But the right way is to correct those intakes.

Agree, I ran an FK87 with 1.4 rockers in a 2110 with 041 & 40x35 valves, DIY port job, dual 44 IDF's, 1-5/8 Berg header and seat of the pants dyno was about 4000 to 7000 rpm.
With 44x37.5 valves seat of the pants dyno was about 3000 to 7200 with slightly more peak power.

YMMV

Wed Sep 10, 2025 7:28 pm

Crower cams part number F24627 = Pauter cams O3E8 .. More lift the better it works. i like 1.4 but 1.3 is safe. I will not nose over just add lift.