Xe285hl cam

-
FWIW, try that Edelbrock out, the engine will like the larger carb better.
 
Rodsaknockin said:
Ok I will give it a shot. Thanks
Click to expand...
Being it is a 750, it is an AFB.
Again, FWIW, these AFB carbs, unless there a tad small for the job, tend not to like the have the gas pedal stomped to wide open throttle when there rolling slow. It’s the weighted air door. Very difficult to add weight to slow it down. Roll into the carb.

Being they have just one set of clusters for the pumpshot. If you have a cluster pack, try the larger cluster if there is a issue with the pump lever arm closest to the carb body for a maximum shot. Back of from there during test and tune. Secondary side is lean OOTB. Even more so for your build. Try enlarging the rear jet by 3 or 4.
 
rods
stock rockers work to .550 I like to oil through the pushrods so use Magnum lifters - with any rocekr
if solid Mike Jones has latest profiles IMHO fill out his cam request form
if roller rockers read all 4 parts of the tech articles on B3 website
with the additional cost of B3 kit to roller rockers the Iron rockers start to look good- get ahold of rocker arm specialists in Redding CA
If rollers no reason not to go 1.6 on intake and one size shorter cam (1.6 and exhaust lobe and extra duration on exhaust would be rpm and exhaust dependent)
I like TQ with AVS second
 
mopowers said:
Which 670 Holley do you have? If it's a street avenger, I'd keep it on the shelf. I tried one on my 340 and it ran like crap. For engines with a bit of camshaft, the idle circuits are way too lean on those carbs. You'll have to open up the idle feed restrictors to keep it from bogging down. The 750dp will be a better carb for the motor IMO.
Click to expand...
And a 2500 rpm stall converter isn't near enough.
 
toolmanmike said:
And a 2500 rpm stall converter isn't near enough.
Click to expand...
Ok point taken if you were going to put a converter in what would your choice be ? The only reason I thought 2500 may work is because I have more compression than they require for the cam so I thought it might work. The other question I have is how do you choose a converter that is going to work well with this combination and still give you some drivability and Iam definitely not opposed to building a stroker I have my block ready and have the kb107s but i will and can go the other way I was going to send my crank in for a polish but I'm not in a panic I have the winter to get it all sorted out thanks for all the help
 
From using a smaller cam but a 10 SCR and 8 DCR on a 340 with a 2200 RPM stall, it is not the least bit soft from a standing start. I don't think 2500 is too small for your larger cubes since you have kept the SCR and DCR up. Easy to change the TC later if you do not like.
 
What does a stock converter brake stall at? 1800-2000? 2500 stall isn't much. Anyone run numbers to see what the torque/hp curves look like?
 
nm9stheham said:
From using a smaller cam but a 10 SCR and 8 DCR on a 340 with a 2200 RPM stall, it is not the least bit soft from a standing start. I don't think 2500 is too small for your larger cubes since you have kept the SCR and DCR up. Easy to change the TC later if you do not like.
Click to expand...
Ok I had one old mopar guy that suggested this cam that with the compression ratio I have the 2500 should be sufficient now with that being said if I do go stroker then a 2500 stall should work really well
 
I run a 276/286/110 HughesFTH (230/237@.050) with a 10.9Scr/8.7Dcr, in a 367,on 87E10 @ 179psi @900ft....... and although it is a standard transmission,it will take a footstomp at under 20mph in second gear, and wind up at 7000 in a heartbeat. that 20mph is 1700rpm. In first gear, I can dump the clutch and stomp it immediately .This with 295s
At your elevation and subsequently lower pressure I would consider the next smaller cam, with 1.6s like Wyrmrider mentions and maybe on a 108.

At 2500ft IMO 11.3Scr is not enough for that 285 cam
IMO it is barely enough for a 272/108 FTH . You will be much happier.
 
Last edited:
AJ/FormS said:
I run a 276/286/110 HughesFTH (230/237@.050) with a 10.9Scr/8.7Dcr, in a 367,on 87E10 @ 179psi @900ft....... and although it is a standard transmission,it will take a footstomp at under 20mph in second gear, and wind up at 7000 in a heartbeat. that 20mph is 1700rpm. In first gear, I can dump the clutch and stomp it immediately .This with 295s
At your elevation and subsequently lower pressure I would consider the next smaller cam, with 1.6s like Wyrm mentions and maybe on a 108.

At 2500ft IMO 11.3Scr is not enough for that 285 cam
IMO it is barely enough for a 272/108 FTH . You will be much happier.
Click to expand...
Ok so I guess the question is I either raise the comp or go to the 274 cam and 1.6 rockers. I really appreciate all the input I want this thing to be as close to the edge as possible. I'm trying to get the best recipe for this engine thanks again
 
Rodsaknockin said:
Ok so I guess the question is I either raise the comp or go to the 274 cam and 1.6 rockers. I really appreciate all the input I want this thing to be as close to the edge as possible. I'm trying to get the best recipe for this engine thanks again
Click to expand...
I think I asked early in the thread, what is this going in?
 
A fast-rate 272/280/110 will be close to the edge for pump gas
Installed at 104 for an Ica of 60* and with an Scr of 11.3@2500 ft the Dcr comes to 9.3 and pressure is predicted to be 185psi@163VP.
If you go down to 800ft, the pressure climbs to 194 and depending on your tuning skills, there may be times when the engine gets into detonation on anything but the best gas
Lets retard it to 106* for an Ica of 62*.. I get 182psi/158VP. Ok that should work.
If your intention is to stay at 2500, then you can run up to 200psi. To do that you would have to decrease the ICA or increase the Scr. The former means less Ica, and the latter means machine work.
The 285/110 has about 68* overlap, while the 272/110 has just 56, so the 272 won't idle as radically as the 285. If this is to be a city car, you can tighten up the 272/110 to as far as 272/104, and get back to 68* overlap for the sound. This will decrease the Ica to 56* and increase the cylinder pressure to a predicted 192psi@174VP a ridiculously high number. This would certainly be on the edge.
Maybe you could get a 276/282/108 In at 106, the Ica would be 64* and the pressure predicted to be 178/152VP there that is more sane.Overlap of 63* so it's getting closer to sounding like the 285 at idle.
>178/152 is about what I run and I have never wished for more

But how about lets go back up to the off-the-shelf 272/280/110 in at 106*this time for an Ica of 62* I get 182@158VP; oh yeah
Lets put it in your car with 4.30s
Your power peak will be near 5400 and a shift rpm of 6200, which will get you 45 in first, and a drop to 3660 into second and 65 will be 5300 badaboom there you go. The quickest way to 65
Or just a whole lotta tirespin.
 
Last edited:
AJ/FormS said:
A fast-rate 272 will be close to the edge for pump gas
Installed at 104 for an Ica of 60* and with an Scr of 11.3@2500 ft the Dcr comes to 9.3 and pressure is predicted to be 185psi@163VP.
If you go down to 800ft, the pressure climbs to 194 and depending on your tuning skills, there may be times when the engine gets into detonation on anything but the best gas.
If your intention is to stay at 2500, then you can run up to 200psi. To do tat you would have to decrease the ICA or increase the Scr. The former means a smaller cam and the latter means machine work.

To be continued
Click to expand...
Ok this info helps a bunch so Iam asking to much for 400hp and 450 tourqe with this set up or Iam going to be in the ball park. My former machine shop didn't want to go even 10.1 comp and more is better lol.
 
I have also been looking at a stroker rotating assembly that will put me in the 12.1 compression area now with that said I will have less because of the elevation most all the time I take my car out it is up to 3300 ft and the lowest would be Medicine Hat at 2260 ft
 
AJ/FormS said:
A fast-rate 272/280/110 will be close to the edge for pump gas
Installed at 104 for an Ica of 60* and with an Scr of 11.3@2500 ft the Dcr comes to 9.3 and pressure is predicted to be 185psi@163VP.
If you go down to 800ft, the pressure climbs to 194 and depending on your tuning skills, there may be times when the engine gets into detonation on anything but the best gas
Lets retard it to 106* for an Ica of 62*.. I get 182psi/158VP. Ok that should work.
If your intention is to stay at 2500, then you can run up to 200psi. To do that you would have to decrease the ICA or increase the Scr. The former means less Ica, and the latter means machine work.
The 285/110 has about 68* overlap, while the 272/110 has just 56, so the 272 won't idle as radically as the 285. If this is to be a city car, you can tighten up the 272/110 to as far as 272/104, and get back to 68* overlap for the sound. This will decrease the Ica to 56* and increase the cylinder pressure to a predicted 192psi@174VP a ridiculously high number. This would certainly be on the edge.
Maybe you could get a 276/282/108 In at 106, the Ica would be 64* and the pressure predicted to be 178/152VP there that is more sane.Overlap of 63* so it's getting closer to sounding like the 285 at idle.
>178/152 is about what I run and I have never wished for more

But how about lets go back up to the off-the-shelf 272/280/110 in at 106*this time for an Ica of 62* I get 182@158VP; oh yeah
Lets put it in your car with 4.30s
Your power peak will be near 5400 and a shift rpm of 6200, which will get you 45 in first, and a drop to 3660 into second and 65 will be 5300 badaboom there you go. The quickest way to 65
Or just a whole lotta tirespin.
Click to expand...
Thanks for the info Iam going to go parts shopping for a cam
 
the Cam should have been picked before or at same time compression chosen.

You seem to be picking compression and band-aid it with a cam.

Smaller than 750 carbs don’t really match 285hl size cam. If you are worried about mileage with a 750 dbl pump, pick a smaller cam and less HP build.

4” stroker with 285hl cam is pushing 500HP.

4” stroker with 9.5:1 compression and 274hl is around 425-450 hp.
 
autoxcuda said:
the Cam should have been picked before or at same time compression chosen.

You seem to be picking compression and band-aid it with a cam.

Smaller than 750 carbs don’t really match 285hl size cam. If you are worried about mileage with a 750 dbl pump, pick a smaller cam and less HP build.

4” stroker with 285hl cam is pushing 500HP.

4” stroker with 9.5:1 compression and 274hl is around 425-450 hp.
Click to expand...

With a 275hl or 285hl with 2500 stall, you'll need a carb with more adjustability than an AFB.

A carb with Throttle plate opening adjustment will likely be needed/helpful. Can help off-idle mild acceleration issues. Also easy and precise float adjustments that Holleys have.
 
Last edited:
What's the rest of your combination? Intake? Heads? Headers? A big cam doesn't always mean big power.
 
toolmanmike said:
What's the rest of your combination? Intake? Heads? Headers? A big cam doesn't always mean big power.
Click to expand...
I was going to run j heads but the machine shop cut into water when they were putting seats in long story.....that would of been at 10:1 with the kb107 and a 68cc combustion chamber according to the kb book any way I decided after doing the porting and having the head ruined I would go with aluminum heads picked edelbrock heads 63cc with 2.02/1.60 valves and performer rpm intake dougs headers the block is bored 40 over and zero decked. I had also picked a xe274hr cam but with the smaller combustion chamber I was steered into the bigger cam for some bleed off. I agree a bigger cam is not always better.
 
Rodsaknockin said:
I was going to run j heads but the machine shop cut into water when they were putting seats in long story.....that would of been at 10:1 with the kb107 and a 68cc combustion chamber according to the kb book any way I decided after doing the porting and having the head ruined I would go with aluminum heads picked edelbrock heads 63cc with 2.02/1.60 valves and performer rpm intake dougs headers the block is bored 40 over and zero decked. I had also picked a xe274hr cam but with the smaller combustion chamber I was steered into the bigger cam for some bleed off. I agree a bigger cam is not always better.
Click to expand...
Aluminum heads with a small chamber are more efficient than cast heads and usually add a point of compression without detonation.
 
Should have bought the larger 65 cc edelbrock heads.

IIRC, the “63cc” head will typically measure 64 cc.

Have a 416 with a similar 274-S cam with 9.7:1 measure compression and im on the edge of pinging with 91 octane pump gas.

Sounds like you had a plan...then the machinist cut into your heads.
 
do not buy a converter till you baseline the one you have
lots of good info since I last looked at your thread
as I said
If you do not have to buy crank and rods run the 360
if you have to do crank and rod work spring for the stroker- unless you are bucks up then go stroker anyway
 
You must log in or register to reply here.
-

Back
Top