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I wish these guys would include the advertised duration!!
There's no way of knowing the speed of that lobe. That adds up to area under the curve as mentioned if the lobe is quick. Output can be achieved with less seat to seat timing.
Fill out a Jones Cams cam recommendation form. He's excellent at replies. And revisions too. He spec'd a potential cam for my "off in the distance" 383. Once I had a chance to look it over, I re-emphasized my performance goals and he cranked out a new spec.
That's better.
Lunati has a decent selection. Vizard was involved with them at one time and there's an entire line of Lunati cam profiles and engine applications in the back of one of his books. Again though, those specs might be outside of the "norm". Once you get into 383 territory, all of the LSAs tighten up. Like to 106.
Now with that 270/278 value and LSA, a true overlap can be calculated and compared to the marine cam. Might be enlightening.
In order to get the same -3 deg on the Voodoo cam, I evidently need to grind it on a 113 LSA. The Voodoo is also on a 106 ICL vs the Xtreme Marine's 110, so again, there's that 4 deg relative retarded ICL on the Xtreme Marine that I'll lose (which should also help with the idle quality).
Lloyd Elliot: 270/278/112. Overlap is 49°.
Comps Extreme Marine: 264/270/112. Overlap is 43°.
Certainly an increase but for a 10:1 383 with those heads, I'd up the ante. Maybe not so much if your compression is on the lower side though.
Comps XR276HR, 276/282/110 has 59° and barely had any lope in the 355. Great street engine that turned out to be with Vortec heads. Idle vacuum IIRC was in the 13-14" range. Cranking compression at about 200 PSI which helps the idle too.
With a 2.02 valve and a 383 I would not run a wider LSA than a 108. You are shooting yourself in the foot torque wise if you do. My 11:1 383 cranks at 240 psi.
In order to get the same -3 deg on the Voodoo cam, I evidently need to grind it on a 113 LSA. The Voodoo is also on a 106 ICL vs the Xtreme Marine's 110, so again, there's that 4 deg relative retarded ICL on the Xtreme Marine that I'll lose (which should also help with the idle quality).
Use advertised rather than .050" for your math. That's the true point where flow is initiated and where differences are made. Same with cranking compression or DCR.
Remember too that all duration values are not created equally. Case in point. Comps XR lobe with 276 adv. has an .050" value of 224 whereas the .050" of their XFI line has an advertised 274 but the same 224. It does make a difference. And idle vacuum (along with other things) is in that difference.
With a 2.02 valve and a 383 I would not run a wider LSA than a 108. You are shooting yourself in the foot torque wise if you do. My 11:1 383 cranks at 240 psi.
I agree. The tighter LSA is the trend for the Gen 1 2.02" valved 383 Chevy. Go to 400 CID and the spec can be tighter still. Just take it easy on the duration.
Although you Mr. Fast has achieved what I was trying to. I could not imagine getting my spec to work with 240 PSI cranking compression. Not that I wouldn't want to.
I agree. The tighter LSA is the trend for the Gen 1 2.02" valved 383 Chevy. Go to 400 CID and the spec can be tighter still. Just take it easy on the duration.
Although you Mr. Fast has achieved what I was trying to. I could not imagine getting my spec to work with 240 PSI cranking compression. Not that I wouldn't want to.
218/228 @ .050 on a 108 LSA and 106 ICL with 1.7 roller rockers and Rhoads V-Max lifters set for 0.020" off the bottom of their travel. 19 in/hg @ 750 rpm with 31° of idle timing advance.
Quench distance, aluminum heads, timing advance curve and coolant temp all play a big part.
Recently tuned a pump gas 13:1 396 LT1. The dynamic compression ratio was 10.6:1 on that engine.
I just setup the cooling system for the 383 though. 34x19x2-5/16 core aluminum radiator, matching shroud and 2 x 16" 3,000 cfm flexalite fans. Running the fans with a BP Automotive GMT800 fan harness and they are setup for dual speeds. PCM controls the fans based off engine temp and a/c pressure. 170°F thermostat and a flowkooler water pump. My goal is to keep it under 180F. Running Peak Final Charge big truck fleet coolant that is good for 8 years or 1,000,000 miles. I also removed the stock, restrictive to airflow 25 year old condenser and put a new parallel flow unit in its place. Condenser change made a huge difference in airflow.
218/228 @ .050 on a 108 LSA and 106 ICL with 1.7 roller rockers and Rhoads V-Max lifters set for 0.020" off the bottom of their travel. 19 in/hg @ 750 rpm with 31° of idle timing advance.
What is the seat to seat duration for that cam? Without taking into account what the bleed down lifters do.
Any issues with the 1.7 rocker?
I just noticed 64cc stamped on the deck. I'll still measure just to be sure. But that at least gets me to 9.5:1. Not terrible I guess. A little conservative in terms of guarding against knocking.
The thing is, the HT383 starts out with a .051" gasket (P/N 12557236). So dropping down to .028 is a pretty decent boost.
271/284...Reliability was the goal, not all out power.
I was thinking more along the lines of valve train geometry. 1.7 was one of those upgrades that I always looked at skeptically because in my lifetime, 1.6 was the limit.
My heads kind of plateau around the .550" mark but with better heads I can see 1.7 as a viable option.
Thanks for the advertised specs. Time for a little math.
dont buy an off the shelf cam..its not 1 size fits all. you need to see what your cylinder pressure is.. the compression,, and what can your heads run.. The diff ratio etc.
it all part of the factor.
David Vizard has a download with over 4000 profiles. He done 11000 dyno runs for comp cams and Crane,, 14000 for Nascar teams, Formula 1 and Pro stock teams over 50 years.
we cant take a guess at what the guy up the road uses.
A custom ground cam for YOUR motor is no more expensive that off the shelf stuff.
Stay away from Hyd Rollers,, the lifters are junk and a good set is very EXPENSIVE....
I run a Solid Cam.
I picked up 83hp with a cam change and its not uncommon to get 100hp and Vizard has all the info on the 100HP CAM.
Get it Polished and Hardened.
good luck
Last edited by aussiesteve; 07-15-2021 at 08:17 PM.
dont buy an off the shelf cam..its not 1 size fits all. you need to see what your cylinder pressure is.. the compression,, and what can your heads run.. The diff ratio etc.
it all part of the factor.
David Vizard has a download with over 4000 profiles. He done 11000 dyno runs for comp cams and Crane,, 14000 for Nascar teams, Formula 1 and Pro stock teams over 50 years.
we cant take a guess at what the guy up the road uses.
A custom ground cam for YOUR motor is no more expensive that off the shelf stuff.
Stay away from Hyd Rollers,, the lifters are junk and a good set is very EXPENSIVE....
dont buy an off the shelf cam..its not 1 size fits all. you need to see what your cylinder pressure is.. the compression,, and what can your heads run.. The diff ratio etc.
it all part of the factor.
David Vizard has a download with over 4000 profiles. He done 11000 dyno runs for comp cams and Crane,, 14000 for Nascar teams, Formula 1 and Pro stock teams over 50 years.
we cant take a guess at what the guy up the road uses.
A custom ground cam for YOUR motor is no more expensive that off the shelf stuff.
Stay away from Hyd Rollers,, the lifters are junk and a good set is very EXPENSIVE....
I run a Solid Cam.
I picked up 83hp with a cam change and its not uncommon to get 100hp and Vizard has all the info on the 100HP CAM.
Get it Polished and Hardened.
good luck
Solid rollers have their place. But despite there advances a Hyd roller is still the more maintenance free option. And even OEM lifters like the LS7 lifters can Rev past 7k today, some upwards of 8000rpm+.
dont buy an off the shelf cam..its not 1 size fits all. you need to see what your cylinder pressure is.. the compression,, and what can your heads run.. The diff ratio etc.
it all part of the factor.
David Vizard has a download with over 4000 profiles. He done 11000 dyno runs for comp cams and Crane,, 14000 for Nascar teams, Formula 1 and Pro stock teams over 50 years.
It's no revelation than I'm a student of Vizard's approach. The next cam I spec, based on multiple sources (Jones, Bullet, Comp, several simulation programs) will follow the DV philosophy. But every single time I post a Vizard spec'd cam, the community gets their underwear in a bunch because the results are out of the norm.
Case in point. A 10.5:1 383 with heads that flow 250-260 and the spec is 283/283, 106-107 LSA. People look at you like you have two heads. 106 LSA !!
Get the (somewhat) free trial download of his Torque Master program and see what kind of results it churns out.
It gets even crazier when you spec a low compression engine and the duration goes up. That started a **** storm of negative comments here at thirdgen. Vizard's reply to my inquiry: "Well, if you can't squeeze it enough, you better be damn sure you fill it as much as possible". His words. Not mine.
Who am I to argue?
The only caveat I can add to his approach is that he's about maximum torque. Everywhere in the rev range. The rest of the pieces will fall into place. Unless you want a pedestrian cruiser.
That approach might even work for the OP, but I'm not going there.
I dont know David,, i never bought from him, i am 61 and only just discovered him this year although i have seen his books for 40 years.
Its a really complicated issue and i found out the hard way from an engine i bought NEW from a shop in AZ.
Got it to Australia and it was a dog,, the cam was crap and the motor had no cylinder pressure,, was at 120lbs and had no power for what it was.
I got an engine guy here to sort it out and we got 88hp and cyl pressure up to 189lbs.
That zizard gets SERIOUS power out of cheap parts,, most of his engines up to 450hp dont even have forged pistons............. he even uses stock rods and says they will run 700hp,, the late 350 LT rods are Powdered metal from GM.. its a Porsche invention for Le mans..
Oh hyd roller cams,,,,,,,,,,,,, DONT BOTHER,,,,,,,,,,,,,,, a flat tappet can kill it and not give problems.. GOOD Hyd Roller lifters are like $750 a set,, or $150 for chinese crap that fall apart. even the big names are using cheap crap and they FAIL..
we put a Solid cam in mu engine and its ALIVE..
Feel free to contact me anytime
Steve in Australia
most oem block guys can use lsx lifters. 12499225. They have gotten much more expensive and harder to find but not 700+. They work fine for hundreds of thousands of miles in oem
applications. I believe they are near 300-350$ now. Its sad cuz they used to be 130$ several years ago lol
if you need a link bar style prices can vary. 500-700+ for sure
id still run a hyd over a solid roller any day of the week. Hyd roller tech has gotten to be very good, lots of good lobes out there and lighter weight spring options. Just so much less concern on maintenance and lifter life
most oem block guys can use lsx lifters. 12499225. They have gotten much more expensive and harder to find but not 700+. They work fine for hundreds of thousands of miles in oem
applications. I believe they are near 300-350$ now. Its sad cuz they used to be 130$ several years ago lol
if you need a link bar style prices can vary. 500-700+ for sure
id still run a hyd over a solid roller any day of the week. Hyd roller tech has gotten to be very good, lots of good lobes out there and lighter weight spring options. Just so much less concern on maintenance and lifter life
I have used Rhoads V-Max roller lifters in several engines now. Whatever you do avoid flat tappet. Every single new flat tappet setup is failing and trashing the engine along with it.
It's no revelation than I'm a student of Vizard's approach. The next cam I spec, based on multiple sources (Jones, Bullet, Comp, several simulation programs) will follow the DV philosophy. But every single time I post a Vizard spec'd cam, the community gets their underwear in a bunch because the results are out of the norm.
Case in point. A 10.5:1 383 with heads that flow 250-260 and the spec is 283/283, 106-107 LSA. People look at you like you have two heads. 106 LSA !!
Get the (somewhat) free trial download of his Torque Master program and see what kind of results it churns out.
It gets even crazier when you spec a low compression engine and the duration goes up. That started a **** storm of negative comments here at thirdgen. Vizard's reply to my inquiry: "Well, if you can't squeeze it enough, you better be damn sure you fill it as much as possible". His words. Not mine.
Who am I to argue?
The only caveat I can add to his approach is that he's about maximum torque. Everywhere in the rev range. The rest of the pieces will fall into place. Unless you want a pedestrian cruiser.
That approach might even work for the OP, but I'm not going there.
People have thought I was crazy for more than 10 years using Vizards theorys.
Whatever you do avoid flat tappet. Every single new flat tappet setup is failing and trashing the engine along with it.
In your opinion, is it the tappets, the lack of ZDDP in today's oils, or a combo of both? Or even lifter bore alignment problems with the camshaft lobe (like the 70's Gen 1 blocks commonly had). Does anyone think that GM relaxed QC in this area once they went to roller lifters?
Last edited by NoEmissions84TA; 07-16-2021 at 05:04 PM.
In your opinion, is it the tappets, the lack of ZDDP in the oils, or a combo of both?
Whenever I hear the knock against flat tappets, I think about the thousands and thousands of circle track engines spinning to 8000 RPM night after night with their flat tappets.
Hmm.
It's a question of quality parts (cam and lifters) AND good oil.
most oem block guys can use lsx lifters. 12499225. They have gotten much more expensive and harder to find but not 700+. They work fine for hundreds of thousands of miles in oem
applications. I believe they are near 300-350$ now. Its sad cuz they used to be 130$ several years ago lol
if you need a link bar style prices can vary. 500-700+ for sure
id still run a hyd over a solid roller any day of the week. Hyd roller tech has gotten to be very good, lots of good lobes out there and lighter weight spring options. Just so much less concern on maintenance and lifter life
I dont want to sound negative but i never see hydraulic roller cams in sprintcars, road racing, power boats, cars under 11 seconds at the strip, and solid flat tappet cams dont need to be adjusted every weekend.
We get 6 to 12 months between adjustment and you can hear it.
Dodge big base lifters are used in goox builds here in Australia with the big base..
I dont want to sound negative but i never see hydraulic roller cams in sprintcars, road racing, power boats, cars under 11 seconds at the strip, and solid flat tappet cams dont need to be adjusted every weekend.
We get 6 to 12 months between adjustment and you can hear it.
Dodge big base lifters are used in goox builds here in Australia with the big base..
Crower, and other top brands made in America will run $500+
I dont want to sound negative but i never see hydraulic roller cams in sprintcars, road racing, power boats, cars under 11 seconds at the strip, and solid flat tappet cams dont need to be adjusted every weekend.
We get 6 to 12 months between adjustment and you can hear it.
Dodge big base lifters are used in goox builds here in Australia with the big base..
in pure racing applications like those, solids are fine and most likely used for durability. If talking street cars that see much more operating time, it can be different. It all depends on how you do it. Plenty of very fast cars in the states with hydraulic rollers. 3000 whp hyd cam viper, 4.50’s and quicker hyd roller 1/8 mile drag cars.
For initial costs, using the oem style dog bone lifter setup and blocks make it very economical. Good solid roller lifters with pressure fed oiling to axles are not cheap either. Most guys with solids tend to run more spring rates and thats where the stress comes in, and why you always hear about solids failing in endurance street applications. Nowadays theres trick cam lobes and conical valve springs and some small diameter light double springs that can take away some of those loads and really get some life out of the lifters. But they will never match a hyd roller that goes 100k miles with a mild lobe cam in daily drivers, but most performance guys dont get near that much life out of their motors before refreshing or changing setups lol. But certainly 5-10k miles a year is in range for a hot performance fun car. For budgetary low medium hp stuff 400-550 hp really no need for these cars to spend money on solid rollers and the little bit of extra work involved. Just my opinion.
i have a solid in my bbc turbo car because with giant steel valves hydraulics just cant work as good, but my first deal had heavy springs and ate a lifter. New setup is much more well designed with modern tech with spring loads like a hydraulic, but it isnt cheap
I have been let down by not doing my homework based on real engineering and trying to use whats good enough. It often has to be done again and paid for twice.
I have been let down by not doing my homework based on real engineering and trying to use whats good enough. It often has to be done again and paid for twice.
i have spent 50 years listening to other people and now ONLY listen to people who dont go with trends or whats fashionable at the time.
The internet is great info but millions of bad advice.
and google mechanics like me.
The people i listen to are at the Top of their field and can and do build championship winning engines from all Brands like Jaguar, Alfa Romao, Mercedes, Harley Davidson and chevrolet and often dont just throw money at it.
Like them stock GM 350 Lt conrods.
Who would know there better than most $700 a set of rods made by who knows.
Its all based on mechanical proof and winners.
I just had a shocking experience buying from a shop in AZ.
I imported a motor thinking i was saving money.
ended up in pieces here in Australia in a shop who said come see your engine before we go furthure
A cam cHange got us 88hp.
And this engine guy here was only $3500 more to do the whole engine but i bought from AZ and got junk we cant even use, cost me $7500
I have been let down by not doing my homework based on real engineering and trying to use whats good enough. It often has to be done again and paid for twice.
There's never enough money to build it right, but there's always enough to build it twice!
In your opinion, is it the tappets, the lack of ZDDP in today's oils, or a combo of both? Or even lifter bore alignment problems with the camshaft lobe (like the 70's Gen 1 blocks commonly had). Does anyone think that GM relaxed QC in this area once they went to roller lifters?
The lifters being machined now are garbage. Comp, Lunati, Melling, they all seem to use the same junk lifter core manufacturer. Most do not even have the correct shape and will never spin. I am on a SBC group on Facebook. Hundreds upon hundreds of failures in the past year.
The lifters being machined now are garbage. Comp, Lunati, Melling, they all seem to use the same junk lifter core manufacturer. Most do not even have the correct shape and will never spin. I am on a SBC group on Facebook. Hundreds upon hundreds of failures in the past year.
The big cam companies have all out sourced from what I can tell. About the only good hydraulic lifter out there that can be trusted is the old stock Delphi two piece. With the hardened foot on the bottom. I have a Melling MTC1 kit with that older design lifter set new in the box still kicking around that I bought about 4 years ago for the 305 TBI I swapped out for a 6.0L in the 87 G20.
Do yourself a favor and pop one lifter apart and measure the pushrod cup.
Unscrupulous people would buy the GM lifter and put the junk knock-off back in the GM box and return it for a refund.
You might have bought GM boxes with crap inside.
The lifters being machined now are garbage. Comp, Lunati, Melling, they all seem to use the same junk lifter core manufacturer. Most do not even have the correct shape and will never spin. I am on a SBC group on Facebook. Hundreds upon hundreds of failures in the past year.
Originally Posted by skinny z
Whenever I hear the knock against flat tappets, I think about the thousands and thousands of circle track engines spinning to 8000 RPM night after night with their flat tappets.
Hmm.
It's a question of quality parts (cam and lifters) AND good oil.
The people with failures are doing it wrong.
While this latest virus thing has messed up the supply chain, in particular with respect to this post and the closing of one of the foundries that make the better lifters for different brands, many, many racers are happily running flat tappets without failure. And putting them through more than anything any of us could do on the street.
As I posted above, you have to find the good parts. Ask Mike at Jones Cams what they sell. He'll set you up with lifters and a cam core that will stand up to a lot of punishment. But there's that supply chain thing again. Plenty of off shore crap available I bet. But the good stuff is harder to source. But it's out there.
If you want more information, check out Speed Talk and search for flat tappets. Volumes of current material to wade through.
As an example, here's Mike's comment on the current state of affairs.
Re: flat tappet cam cores - what's the status in 2021?
Post by CamKing » Thu Mar 18, 2021 8:31 am
Flat tappet core quality is fine, as long as you go with a quality US made core.
Flat tappet cams are not going away, any time soon.
About 70% of all circle track race engines are required to run flat tappet cams, That's still a huge number of cams.
In the last 12 months, flat tappet cams made up 35% of my cam sales.
The same holds true for lifters as well. Just saying....
I'm a roller guy myself. Having had a flat hydraulic go flat on me convinced that I don't want the risk. That said, I was doing it wrong too. In this case, it was a question of poor engine maintenance. I should have known better.
Racing sanctions are out dated with dumb rules lol. Doesnt make it a good thing. Flat tappets should never have came into existence lol they had rollers back in the 19-teens and 1920’s lol.
That doesn't mean that they aren't perfectly capable of doing what they're supposed to.
What your preference is isn't the issue here. I'm a roller guy too as I said.
But the knock against flats as always failure prone is incorrect. And I'm only pointing that out.
And there are still plenty out there.
While we are on the subject, does anyone know the weight difference between a flat tappet lifter and a roller?
And how does that extra weight from the roller affect rpm potential? Just this one parameter - not "with the proper springs and...………, a roller setup can rev higher...…….."
From the Comp catalogue:
Hydraulic flat. 94-99g.
Solid flat. 109g.
OE hydraulic roller. 122g.
Link bar hydraulic roller. 136g.
Short travel link bar hydraulic rollers. 152g.
Solid rollers are all over the map. High and low.
That's just one brand though. Anybody else's could be different.
I am surprised that the solid flat weighs MORE than the HYD flat.
The solid does not have the "pumping mechanism" inside.
Oil weighs more than cast iron?
What am I missing here?
The solid is solid. More or less. The hydraulic has big hole down its centerline. That's quite a bit of material removed isn't it? The metering disc and spring don't fill that slug of metal removed.. Neither does the oil.
At least that's my take on it.
What really surprised is the short travel link bar hydraulic, owned by yours truly, they are slugs. Tool steel I know rather than cast. And I suppose there's less of a cavity to fill with oil so again there's more metal. But significantly heavy.
There's the importance of the correct spring.
I am going to dig my digital scale out tonight. SBC flat tappet - HYD vs SOLID weights.
Results -
Hydraulic flat (Crane 99277) - 97g.
Crower Solid flat. 82g.
Old Crane Cams link bar solid roller (Ultra Pro series 11542) - 205g for the pair.
Correction - The Crower Solid flat (66900-3) is 87g.
The lightweight of the bunch is a generic solid flat tappet from PAW weighing 82g. Anyone remember PAW in California?
Last edited by NoEmissions84TA; 07-23-2021 at 05:53 PM.
I am going to dig my digital scale out tonight. SBC flat tappet - HYD vs SOLID weights.
Results -
Hydraulic flat (Crane 99277) - 97g.
Crower Solid flat. 82g.
Old Crane Cams link bar solid roller (Ultra Pro series 11542) - 205g for the pair.
Correction - The Crower Solid flat (66900-3) is 87g.
Now I'm going to have to dig through my catalogues to see if I can find that lightweight solid. The hydraulic flat looks about right though.
That said, the Crane stuff appears to quite different in weights when compared to COMP. Lighter and heavier. Haven't checked Crower
I have a bret bauer specc'ed cam collecting dust in the garage only because I put a blower cam in the car. That cam is 230-230. 600-.600 107lsa and kicked *** everywhere. My heads were bigger (215 cc) and flow more than the AFR 180 heads you are using and I had 10.5:1 compression but it made 365 to the wheels around 6300 rpm and ran 11.60-11.70's at 116-117 all day long with a 3.73 gear and 3500 stall. Idle was rock solid at 900rpm. I wouldn't hesitate to use that cam again in a 383 or 350. Don't be afraid of the 107lsa, it is very tuneable despite what people think. The cam that was in the car before this one was one from advanced induction and was 242-248 580-600 on a 110lsa. I had no power brakes at all with that cam and a vacuum canister barely helped. Had to have the idle at 1200 rpm to have vacuum. Didn't make any more power either.
I have used the old LPE 219 cam at 219-219 .525.525 on a 112 lsa but I used 1.6 rockers for .560 lift. That cam kicked *** also, but I used it with a superram instead of the miniram I have now.
I had Lloyd Elliot port my heads years ago and Bauer do the cam. Whatever Lloyd says will work, he knows what he is doing.
That cam is 230-230. 600-.600 107lsa and kicked *** everywhere.
Don't be afraid of the 107lsa, it is very tuneable despite what people think..
That's an interesting spec. Do you have the advertised/seat to seat (.006") for that cam?
As for the 107 LSA, I'm thinking most novices don't understand what it means in terms in performance or tuning. The 107 is meaningless unless the duration is known.
That cam is in storage right now with the cam card, sorry.
Here is an email from him on the cam specs:The cam I came up with should give you the same HP, more TQ and 30% more idle vacuum so you can live with the thing. I included a simulated dyno chart for you on that.... As you can see more TQ, the same HP and with the lower overlap now a bunch more vacuum. The old cam had 28° of overlap at .050, no wonder it drove like crap, I dropped that down to 16° of overlap at .050.
New cam specs are 230/230 .600/.600 (with 1.6's) on a 107LSA.... most people flip out about low LSA's but as you can see the overlap is much lower than the old cam with a 110LSA so it doesn't tell the whole story if you just look at that.
I used to know that info. I believe its a comp magnum high lift lobe, 286 advertised 230 at .050
around that time of the lloyd elliott LE2-LE3 packages, bret was doing the cams and he did one for my 383 that used the 230 .603” lobe which was a magnum high lift, but it was on a 109 lsa and a 245 deg exhaust side, which suprised me but he said the stealth ram requires alittle different specs than a Lt1 ultra short runner and i also was gonna spray the car 150.
Bret has done my last two turbo cams and i have been very happy
[QUOTE=89gta383;6437678]That cam is in storage right now with the cam card, sorry. [QUOTE]
No worries.
[QUOTE=Orr89RocZ;6437679]I used to know that info. I believe its a comp magnum high lift lobe, 286 advertised 230 at .050...[QUOTE]
If that's the case, it's the same overlap (71 vs 72 degrees) as the XR 288 I have now and very tunable. Even with a carb and manual ignition.
Never thought much about the Magnum lobes but they might be worth investigating.
I'm thinking the 383 can swallow up another 5-7 degrees of overlap and have the same characteristics as the 350.
Something like a 288/288 on a 106 LSA.
What I have to determine now is where to draw the line on the intensity scale. I'll give up some area under the curve for the sake of durability. A lot more to it than that obviously but it's the direction I've got to explore.
07-13-2021, 07:41 PM
