Cam comparison

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In comparing camshafts, you’ll need to find out the rate of lift of the cam lobe to start. This starts with where the advertised duration is measured. Is at .002? .007? .010? Then again at various lift points like 020, 030, etc and finally at .050. This should draw a curve. Then there is actual lobe lift at these points. Then max lift. Overlap, LSA.

Once you can find these specs and draw a curve out on both cams, then you can see which one has the most area under the curve. The fatter the area, the more quickly the valve lifts to a greater spot with more head flow capabilities. This equals power.

In the case of the HFT XE285HL, a more powerful cam will have the same (or super close) advertised duration but an increase of the .050 duration. The rest of the cam specs, overlap and LSA and lift remain the same.

If you like the XE285HL but want a mild power increase, follow the above points to compare cams. The quicker you can lift the valve and hang it open for a greater period of time or degrees, the more power you will make and if the rest of the specs remain the same, perform in the same rpm band and have the same majors as the HFT did.

Being you have a manual transmission and hyd/boost brakes, don’t be afraid of a cam on a LSA of 106 or 104. It’s just a mild pressurized GN of the gas pedal to up the rpm of the engine to engage the clutch not really any different than a stock cam on a wide centerline. It’s just the idle itself being choppy won’t allow a near idle engagement of the clutch very nicely.
 
Call Howard’s and see if they can make that cam fresh for you on a 106 or a 104. (104 is better IMO.)
 
Howards sells quite a few of those cams going by the in and out of stock status at Competition Products. That may or may not be helpful as far as lead time on a custom grind is concerned, but it does appear to have a repeat customer base.
 
rumblefish360 said:
@dukeboy_318 The rhythm of your exhaust note is given by the LSA of the cam. The sound at the tailpipe end is mostly due to the muffler though header and exhaust pipe diameter play a small part.

The smaller the number on the LSA will normally lead to an idle that has a chopping sound. More directly related is the amount of overlap. More overlap, the rougher the idle.

Since vacuum isn’t a concern, a cam with a LSA of 106. The amount of overlap should be somewhere between 70 - 90 degrees. The more overlap, if you can find that information, will lead to 2 things, a rougher idle and a higher rpm band where peak power is made.

If you like where your current or past cam performs AND you want a slight rise in high end rpm power, increase the overlap. If your 440 intake valve is smaller than 2.19, increase the LSA by 2*’s max.

The difference between a hydraulic and a roller depends on the build. Your build is mild with the 10-1 ratio and cylinder head choice. I don’t see a big gain at all as also mentioned above, 17 hp is not a lot.

The choice of cam style is purely your choice. Build it once and don’t stray from the plan. It’ll only cost you more money in 90% of the time.

I have no experience with big block heads. You’ll have to wait for the been there and done that crew to show up. BUT! I can tell you about my small block head adventures. Most pushrod holes will accept a larger pushrod without much ram fair if any at all. However, a switch from a hydraulic or SFT cam to a roller or any style will require a shorter pushrod. The PROBLEM is the taller lifter creating an aggravated angle of the pushrod that will collide with the cylinder head in the pushrod tube. While the rod is not hard even with a tiny dremel die grinder, a real die grinder should be used.

You can easily run a stock diameter P-rod at a thicker wall & a stock diameter. I’m not sure if a larger 3/8 diameter P-rod will work OOTB with a HFT/SFT cam & the Edelbrock heads.
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Thanks!!
 
dukeboy_318 said:
So I’m mostly worried about the flat tappet issue that seems to be plaguing the industry right now. Since 2020, out of the 23 in our car club, 19 have had their flat tappets wipe. And some of these guys have been been hot rods since the 50s.

The last one that just had his wipe was in an engine built for his drag car by a professional Indy car team in Speedway. Last 14 miles after breaking in on the dyno. Hydraulic lifter failed
Click to expand...
So was I, ESPECIALLY after losing 9 or more lobes very recently on an engine break in I did on a Chevy 402........and I did everything right. First time I have EVER flattened a cam on an engine since I've been working on cars. Yes , it was a Comp Thumpr hydraulic flat tappet.

That said, I was really nervous when I recently finished the engine swap on my 75 F250, Gladys. I've had the 400 for her built and stashed for a few years. Did everything right there. Initial fire up went fine. After it got good and up to operating temp, I could hear the lifters ticking. I was sweating bullets. I put probably 200 miles on it and it got no worse but got no better.

I changed the preload several different ways. Although the rockers are non adjustable, the rocker pivots can be shimmed to change preload. I tried light preload, medium, and heavy. No change. This was with expensive Crower Cam Saver lifters.

I said screw it and tore back into it and replaced those high dollar lifters with stock Melling $4.99 a piece lifters from Summit. Broke it back in and it's been quiet as a MOUSE and running great ever since. Talk about dodging a bullet. The Crower lifters looked great as for breakin wear, so the ticking was in the valving of the lifters themselves. So I cannot recommend the Crowers.
 
I only cam that wiped out on me was a Summit cam.
Reinstalled a Comp Thumper (that was reserved for another engine) and everything is fine. IMO, it’s hit and miss.
 
RustyRatRod said:
So was I, ESPECIALLY after losing 9 or more lobes very recently on an engine break in I did on a Chevy 402........and I did everything right. First time I have EVER flattened a cam on an engine since I've been working on cars. Yes , it was a Comp Thumpr hydraulic flat tappet.

That said, I was really nervous when I recently finished the engine swap on my 75 F250, Gladys. I've had the 400 for her built and stashed for a few years. Did everything right there. Initial fire up went fine. After it got good and up to operating temp, I could hear the lifters ticking. I was sweating bullets. I put probably 200 miles on it and it got no worse but got no better.

I changed the preload several different ways. Although the rockers are non adjustable, the rocker pivots can be shimmed to change preload. I tried light preload, medium, and heavy. No change. This was with expensive Crower Cam Saver lifters.

I said screw it and tore back into it and replaced those high dollar lifters with stock Melling $4.99 a piece lifters from Summit. Broke it back in and it's been quiet as a MOUSE and running great ever since. Talk about dodging a bullet. The Crower lifters looked great as for breakin wear, so the ticking was in the valving of the lifters themselves. So I cannot recommend the Crowers.
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I was thinking of doing the Rhodes Vmax lifters they seem to have great reviews
 
If you don't want flat tappet lifter failure, find some NOS lifters that are 25+ yrs old...or have a set of factory lifters re-faced.
Also, overlap is what gives you the throaty exh note, not LSA. All these 'trick cams' with the fancy names such Crumper, Whiptrash, Bootcrapper have 10-15* more exh duration to increase overlap. If the exh duration was reduced to be the same as the int & the same LSA used, the exh note/sound would be much more subdued.
 
Bewy said:
If you don't want flat tappet lifter failure, find some NOS lifters that are 25+ yrs old...or have a set of factory lifters re-faced.
Also, overlap is what gives you the throaty exh note, not LSA. All these 'trick cams' with the fancy names such Crumper, Whiptrash, Bootcrapper have 10-15* more exh duration to increase overlap. If the exh duration was reduced to be the same as the int & the same LSA used, the exh note/sound would be much more subdued.
Click to expand...
Overlap PLUS a wide duration split. To say LSA has no effect at all on sound is just not true.
 
blip......... blip........ blip.........
I like the popcorn popping sound.:D
blippitty... blip...blippitty...blip.
 
Bewy said:
If you don't want flat tappet lifter failure, find some NOS lifters that are 25+ yrs old...or have a set of factory lifters re-faced.
Also, overlap is what gives you the throaty exh note, not LSA. All these 'trick cams' with the fancy names such Crumper, Whiptrash, Bootcrapper have 10-15* more exh duration to increase overlap. If the exh duration was reduced to be the same as the int & the same LSA used, the exh note/sound would be much more subdued.
Click to expand...
Let me rephrase. I want durability, performance and lastly , a decent rumble to the exhaust. Nothing overly crazy
 
RRR,
I should have been more specific. I was responding to an earlier post that claimed the exh note was determined by LSA...no mention of other aspects of valve timing.
You can get a cam with 102 LSA, 185* @ 050 , & it will have a smooth idle & not have a rowdy exh. Use the same 102 LSA but increase duration to say 230 @ 050 & it will have a very rowdy exh; increase the exh duration on the last cam by another 15* & the exh will get even raspier....because overlap has increased.
The above was one of David Vizard's tenets: if you want a smoother idle & more low end, do NOT increase LSA, instead reduce duration.
DVs SB Chev book has 3.5 pages of Lunati cams with part #s, with 6 or 7 categories, from mild to wild...
The mildest category, Street & Tow has the same duration for engine sizes 302 through to 434 [ stroker ]. What differs is the LSA: 110 to 104. The duration @ 050 is 199*.
From Street & Tow to the other extreme is Real Race. Same LSAs but more duration 244 & 050
The LSA & duration can be used to vary the overlap, but both will change the overlap.
 
fishmens67 said:
blip......... blip........ blip.........
I like the popcorn popping sound.:D
blippitty... blip...blippitty...blip.
Click to expand...
I'm a fan of potato-potato-potato-potato

FWIW I recently bought a Howard's cam that was ground and drop-shipped from the factory. Took a couple of weeks or so. They don't use the plastic cam boxes any more.
 
Bewy said:
RRR,
I should have been more specific. I was responding to an earlier post that claimed the exh note was determined by LSA...no mention of other aspects of valve timing.
Click to expand...
That be me and….. that first sentence also applies to me.
However….
Bewy said:
You can get a cam with 102 LSA, 185* @ 050 , & it will have a smooth idle & not have a rowdy exh. Use the same 102 LSA but increase duration to say 230 @ 050 & it will have a very rowdy exh; increase the exh duration on the last cam by another 15* & the exh will get even raspier....because overlap has increased.
The above was one of David Vizard's tenets: if you want a smoother idle & more low end, do NOT increase LSA, instead reduce duration.
DVs SB Chev book has 3.5 pages of Lunati cams with part #s, with 6 or 7 categories, from mild to wild...
The mildest category, Street & Tow has the same duration for engine sizes 302 through to 434 [ stroker ]. What differs is the LSA: 110 to 104. The duration @ 050 is 199*.
From Street & Tow to the other extreme is Real Race. Same LSAs but more duration 244 & 050
The LSA & duration can be used to vary the overlap, but both will change the overlap.
Click to expand...
Good addition to the thread. To include everything and the parts that need an adjustment, addendum as well as nuances to camshafts, the post could get super lengthy.

I want an extended personal thanks for that post and what you said within it to mine and the camshaft writings. The valve timing is super important should anybody care to make the best of what they’re doing. It’s not easy to quickly explain such things. Especially if someone wants details and wants to slice things up and pick them apart. This is one of the reasons why I don’t suggest cams anymore. Everybody has their opinion on what to someone should wear, what they should be drinking just like what intake, carb, air cleaner, etc….

Many people that make a camshaft suggestion can have a merit, but, it doesn’t always fit exactly what the person wants to do or what they’re looking for. Like everybody else here I can make some generalizations and simple suggestions I can’t make anything exact. In short, there’s always a better camshaft.
The challenge is to get the best one for you.

Again I like to make a public “Thank You” to Bewy.
Camshafts can be super complex. Never mind an internet board selecting the right one for you. Call up the various camshaft grinders and they even come up with different grinds. Call 10 grinders, get 10 different answers.
 
RustyRatRod said:
You do get it right every now and then. lol
Click to expand...
Thanks. Sometimes I care a little more than others and actually have the brain on 11. Now, if I could dial it up manually, I’d do it all the time.
 
I run a Comp Cams XR274R Solid Roller in my 499" RB street engine. 236/242 @ .050" .564"/ .570"

Xtreme Energy 236/242 Solid Roller Cam (3 Bolt) for Chrysler 383-440

Just remember the way the lobes are shaped on a roller vs the lobes are on flat tappet cam changes the way it works.

While this might not sound like a big cam to those who aren't familiar with roller cams it's effectively 8-10 degrees more duration than a flat tappet cam of the same duration.

There is nothing worse than a poor performing engine because it's over cammed, or worse yet someone using a Thumper cam because they want it to sound mean.

If you want a big block that runs extremely well, then I would suggest using a XR274R cam.

Tom
 
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