Opinions on cam driveability; anyone running a 704 Lunati, Comp XE285HL, Howards 721201-08 or Hughes 3642-08 or similar?

[magster65]

I'm selecting a cam and thinking these hydraulic flat tappet units are in the range.
The car is basically a Saturday night special... but we do some highway road trips too. I don't care if I give up some low end for a better sound and top end!
I'd like to hear your experience driving with something like these. Wish you went a bit more? Bit less? Shitty in stop and go traffic? Heats up? Regret not going to a solid?
It's a 440-6v, TF 240's, 10 to 1, Tremec, 4.10s.
Cheers

 

[Black_Sheep]

If you have the cam specs please post them, I’m too lazy to look them up…

 

[Kern Dog]

The Comp 285 was a good design yet I still managed to wipe out two of them in a row despite proper break in.
This was in 2006 when the cam and lifter problems seemed to be really bad. Maybe they have improved since then? I've only wiped out one cam since 2009.

 

[threewood]

I have a Hughes STL3842 solid lifter cam and it is very drivable. Good power. I have considered going with something with a little more duration though.

 

[Fran Blacker]

4.10's I have driveabilty problem with. OK but rough on driving over 50 mph (80 kph) or 30 miles (42 kilo) in any direction. Fun gears! MO

 

[rumblefish360]

I run a modified XE285HL from a 110 to 108 LSA in a 10.5-1 340 in a ‘71 Duster. For a hyd cam, it’s pretty good and on target for a nice “Saturday night special” engine.

Being it’s a 241/247@050 w/.545 lift, it’s right in that ball park for a street hot rod camshaft. IMO anyway. It works well with the ported heads, a 750 & RPM intake.

Overall, I like it.

What you need to do is figure out the amount of overlap needed for your application and the duration for the street. Your LSA should be ether side of 105 for best torque production.

 

[furious70]

528 solid?
I wish we had done that vs the hyd 484 in my charger. It was my dad's and he didn't want to worry about a solid even though he rarely drove it after break in

 

[magster65]

If you have the cam specs please post them, I’m too lazy to look them up…

Howards - 238/242 .555/.562 @ 108
Hughes - 236/242 .546/.562 @ 108
Lunati - 238/242 .513/.533 @ 110
Comp - 241/247 .545/.545 @ 110

The Comp 285 was a good design yet I still managed to wipe out two of them in a row despite proper break in.
This was in 2006 when the cam and lifter problems seemed to be really bad. Maybe they have improved since then? I've only wiped out one cam since 2009.

We haven't used a lot of Comp cams lately... only a couple 268's in some Chevys. They've been great so I'd try one.

I have a Hughes STL3842 solid lifter cam and it is very drivable. Good power. I have considered going with something with a little more duration though.

Those numbers are similar. More duration because it runs out of power or it doesn't sound right?

I run a modified XE285HL from a 110 to 108 LSA in a 10.5-1 340 in a ‘71 Duster. For a hyd cam, it’s pretty good and on target for a nice “Saturday night special” engine.

Being it’s a 241/247@050 w/.545 lift, it’s right in that ball park for a street hot rod camshaft. IMO anyway. It works well with the ported heads, a 750 & RPM intake.

Overall, I like it.

What you need to do is figure out the amount of overlap needed for your application and the duration for the street. Your LSA should be ether side of 105 for best torque production.

I watched the Visard 128 "rule" video. I haven't tried a 105 but the 108 cams numbers do look good on the desktop comparatively. Similar top end but just like you say, more average torque at lower rpms.
I'm guessing these cams would all work well and maybe I should stick to the tighter LSA?

528 solid?
I wish we had done that vs the hyd 484 in my charger. It was my dad's and he didn't want to worry about a solid even though he rarely drove it after break in

I looked at that... solid or hydraulic... hmmm.

4.10's I have driveabilty problem with. OK but rough on driving over 50 mph (80 kph) or 30 miles (42 kilo) in any direction. Fun gears! MO

I'll be running a Tremec 5 or 6 speed.

 

[threewood]

More duration for higher power band. It has a ton down low already, even with a Street Dominator single plane.

 

[magster65]

I have no idea what the cam is that's in it now. Any guesses?

 

[dadsbee]

Stock... not that there's anything wrong with that....

 

[rumblefish360]

@magster65 The 105 follows DV’s 128 rule, which is set up for a 10.5-1 engine. If you have more than 10.5-1, the thought here is you can get away with less or a 108. The extra compression (1 pt higher let’s say) can help lead to a better intake pull.

IMO, the 108 LSA would be fine. A 106 is just better. Plus or minus 1 degree isn’t a worry point. 2*’s from optimal shows a minor difference. 4*’s shows more, 6*’s is showing a bunch & will probably have an idle like what cranky old grandma likes.

My 340 w/a 2/08 valve calls for a 128 rule LSA of 109.40
The 360 with a 2.08 - 108.32
The 360 w/a 2.02 - 107.72

Smaller the valve the lower the LSA to help start the fuel pull.

The tighter the LSA, the rougher the idle and often lower vacuum.

 

[magster65]

@magster65 The 105 follows DV’s 128 rule, which is set up for a 10.5-1 engine. If you have more than 10.5-1, the thought here is you can get away with less or a 108. The extra compression (1 pt higher let’s say) can help lead to a better intake pull.

IMO, the 108 LSA would be fine. A 106 is just better. Plus or minus 1 degree isn’t a worry point. 2*’s from optimal shows a minor difference. 4*’s shows more, 6*’s is showing a bunch & will probably have an idle like what cranky old grandma likes.

My 340 w/a 2/08 valve calls for a 128 rule LSA of 109.40
The 360 with a 2.08 - 108.32
The 360 w/a 2.02 - 107.72

Smaller the valve the lower the LSA to help start the fuel pull.

The tighter the LSA, the rougher the idle and often lower vacuum.

100% on that. No cranky gramma cams!
The 108 LSA it is so... for 6000 rpm, the Hughes and Howards are there.
23/24 overlap should sound nice.
Thank for the input!

 

[moparker]

I have a 704 in my 340. You will need to run adjustable rockers. Its a noisey cam. Idles fine and sounds good.

 

[Black_Sheep]

With the manual transmission and 4.10’s the drivability will be fine. I have a Mopar .509/292 in the GTX, it’s [email protected] with.509 lift and a 108 LSA. Vacuum at idle is a little low but once I got the carb and ignition dialed in it really is a well mannered cruiser with a 3500 stall converter and 4.10’s. No OD so rpm’s on the highway are about 4K @ 70 mph, but it’s up on the cam and seems to like it. Obviously the fuel economy isn’t great but that’s not what I built it for…

 

[rumblefish360]

100% on that. No cranky gramma cams!
The 108 LSA it is so... for 6000 rpm, the Hughes and Howards are there.
23/24 overlap should sound nice.
Thank for the input!

I wouldn’t purchase a cam based on the LSA alone since the other companies can alter the timing for you like Comp did for me.
If their cam spec suite the build, that’s what you’re after. Not just the LSA.

Where and how did you get the over lap “23/24” numbers?

Below a quick chart from David Vizards book on the overlap estimate you should be looking at.

 

[rumblefish360]

Here is a small hyd I’ll be using in a cruiser w/3.55’s & a 727 w/a 2500 stall on 245/60/15’s. It’s a 2000, 5.9 with 2.02 Magnum R/T heads flowing 240 cfm+ at .500. Remember the Magnum heads have a 1.6 rocker which changes the valve lift to .539.

The whole idea of this is just a driver with enough power to get on and pass on the interstate with ease.

The rest of the engine is a 750 carb, RPM intake, Hooker Super Comp headers @ 1-3/4 into a 2-1/2 exhaust. MP distributor triggered by a chrome box.

This cam met the specs and with a 108 LSA.

 

[Geoff 2]

Rumble,
I am an admirer of DVs work but I think he did a disservice publishing that overlap chart because it is based on advertised duration, not 050 duration. 050 duration of course is...050 duration. But adv duration can be anywhere from .000" to 0.008" tappet lift. That variation can amount to a substantial amount. He doesn't specify at what tappet lift those numbers were generated.
The numbers in his SBC book vary slightly from the chart in post #16. 10-35 v 10-40. 90-115 v 95-115.

 

[magster65]

Haha... I'm going to go out on a limb here and say that nobody on this planet would select a cam based on LSA alone! My overlap numbers are from the .050 like the desk dyno does when you enter the specs.
Using advertised duration numbers, the Howards cam is 71 degrees, "4" on DV's chart. Hughes only uses an .050 and doesn't even give an advertised duration... but it's basically the same.

I wouldn’t purchase a cam based on the LSA alone since the other companies can alter the timing for you like Comp did for me.
If their cam spec suite the build, that’s what you’re after. Not just the LSA.

Where and how did you get the over lap “23/24” numbers?

Below a quick chart from David Vizards book on the overlap estimate you should be looking at.View attachment 1555814View attachment 1555815

 

[rumblefish360]

Rumble,
I am an admirer of DVs work but I think he did a disservice publishing that overlap chart because it is based on advertised duration, not 050 duration. 050 duration of course is...050 duration. But adv duration can be anywhere from .000" to 0.008" tappet lift. That variation can amount to a substantial amount. He doesn't specify at what tappet lift those numbers were generated.
The numbers in his SBC book vary slightly from the chart in post #16. 10-35 v 10-40. 90-115 v 95-115.

IMO, anyone who is serious and has been around the block wouldn’t be worried about the advertised numbers immediately. Once the basic idea of what the DV numbers would spec, the next logical step would be to look for that cam lobe with a high lift rate, or steep ramp to get that valve up as quick as possible.
This live style I haven’t seen with a low slow ramp rate unless it’s a roller cam, which can not do this.

Looking at the advertised rating and it’s variances knowing you want the valve up as quick as possible is part of the search.

I know who misses that. New guys. From what I have seen on the dyno, it’s not a huge deal but it’s there. The only thing left is, in the difference, is the short coming a problem in the rpm your after and if so, is it in the driving/cruse range.

As a basic… when I’m after the most and best cam I can find for the HP driver street strip car, the less difference between advertised and the @050 I can find normally has the most aggressive lobe.

Cam manufacturers normally don’t supply lift numbers other than they’re advertised and at 050. Also there advertised point isn’t always made know ether. Another hinderance for the home hot rodder.