Advice needed

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Ozcuda

Ozcuda

gotta love a MOPAR
Joined
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Hi Guy's,

Well got my stroker kit from CNC great guys to deal with reasonable prices & shipping very helpful.

So now I will be pulling the engine in the next few weeks I have to drop it at the engine shop to get machined to fit the stroker crank. I am running the flat top pistons hopeing to get about 11.3 to 1 comp.

Now my engine guy recommends that I get a bigger cam.

I am running ported & polished 2.02 / 1.85 J heads that flow 239cfm inlet & 184 cfm exh.
The guy who done the heads recommended a cam between 525 & 535 lift. So I have been running a comp cam #20-227-4 it seems to be working fine as I have run a 12.81 @ 105.3 in a 3300lb car + me (yeah I know the car & me both need to go on a diet).

Car is also fitted with port matched RPM airgap, 750carb, custom made headers, Rear is 3.9 to 1 & 727 has stage 2 shift kit, HD internals & 2500 stall...I will be getting a new 3000 stall & manual valve body.

I want to know if there will be any benifit to go to a bigger cam ???

Thanks OZ
 
The problem with the words "Bigger cam" is do you mean more lift or duration.

Duration dictates RPM band of which the engine operates in.

Lift has a direct impact on HP, but how much lift the head can handle is in question.
 
The XE275HL is a fairly mild hydraulic for a 408 stroker.

Remember strokers will soak up around 8 degrees duration over a std stroke SB

Personally though I reckon your bigger problem is in your heads - if you want to "go deep" into the 12s...., you really need around 250cfm peak to match a cam that will work to 6000 rpm in that build.

I'd doubt your making peak HP much past 5000 with that combo unfortunately.

Whats your shift point?

FWIW, I have a very similar build with heads that flow 243@ .550, i run a 245/252 duration cam with .520/.540 lift, same 3.89 gears as you and a fatter 3650 lb car.

My best is 12.3 at 111mph - with a very ordinary 60ft.

Your MPH is way low and its the heads and cam thats doing it IMHO.
 
105 mph is spot on with a 12.81, That car with a 11:1 stroker should be in the 11's
My 360 at 9:1 and 2900 lbs runs 11:60's with a lot less head and cam
What RPM do you shift at, I would suggest no more than 5500
A cam in the 250 @ 050 range would probably help a lot
 
rumblefish360 said:
The problem with the words "Bigger cam" is do you mean more lift or duration.

Duration dictates RPM band of which the engine operates in.

Lift has a direct impact on HP, but how much lift the head can handle is in question.
Click to expand...

I'm not sure I will ask him but I would think he means a little more lift & more duration as well.
The guy who done my heads said that 525 to 535 lift is all the heads can handle any more & there is no benifit.

He has since retired so I have gone to a new engine shop & they recon that I will benifit from a bigger cam. I just don't understand how if the cam I have is able to flow all the heads are able to how fitting a bigger cam will help.

The guy at the engine shop is aiming for 550HP out of the set up he is building for me.

Cheers Oz
 
my 70 duster thats 3200 with me went 7.44 with 240/140 at 500 and a comp 282xs cam 520/540 the mph was down and the 60 was **** if i could had a better hook the car would have been faster 60' times best was 1.67 and best mph was 90 most of the time was 89. something.....i really like the comp cam its nice on the street and great at the track....oh i had a 950 carb on it aswell mike
 
Rat Patrol said:
The XE275HL is a fairly mild hydraulic for a 408 stroker.

Remember strokers will soak up around 8 degrees duration over a std stroke SB

Personally though I reckon your bigger problem is in your heads - if you want to "go deep" into the 12s...., you really need around 250cfm peak to match a cam that will work to 6000 rpm in that build.

I'd doubt your making peak HP much past 5000 with that combo unfortunately.

Whats your shift point?

FWIW, I have a very similar build with heads that flow 243@ .550, i run a 245/252 duration cam with .520/.540 lift, same 3.89 gears as you and a fatter 3650 lb car.

My best is 12.3 at 111mph - with a very ordinary 60ft.

Your MPH is way low and its the heads and cam thats doing it IMHO.
Click to expand...

1 fst Dart said:
105 mph is spot on with a 12.81, That car with a 11:1 stroker should be in the 11's
My 360 at 9:1 and 2900 lbs runs 11:60's with a lot less head and cam
What RPM do you shift at, I would suggest no more than 5500
A cam in the 250 @ 050 range would probably help a lot
Click to expand...

Hi guy's,

I shift anywhere from 5500 to 6200 motor falls over at 6600. Car with me in it is around 3500lb the old wagon is still street driven to & from the strip.

The guy who done my heads is an old drag racer from way back used to run street cars in the 60's & made his way up to Pro stock's even though he has retired he is still building drag motors for super charged outlaw cars & such. When we ran our first 13.0@ 102mph he said that he didn't think that the car could do it then we had the headers made & I mades a set of chassis connectors & we dropped into high 12's & he was gob smacked.

I don't know what power it is making now to run 12.8 but I asume that if we can get the new motor to anywhere near 500+ it will be all good. I would love to run consistant 11.8.
 
Im not an expert but theres NO WAY your gonna have 550hp with a head that flows only 239cfm. My J-heads with 2.02/1.60 valves flow 284@525/530 and im hoping to have around 500hp-525hp.
 
mikesduster said:
Im not an expert but theres NO WAY your gonna have 550hp with a head that flows only 239cfm. My J-heads with 2.02/1.60 valves flow 284@525/530 and im hoping to have around 500hp-525hp.
Click to expand...

Hey Mike,

I don't know what HP it will make the engine guy said he is hoping for 550HP weather it does or doesn't who knows I don't really care either way as long as it runs hard.

I will have to dig out the paper work for the heads I might be wrong but I remember when I picked the heads up the guy told me that they were capable of over 500HP I just had to get the rest of the motor there.

I guess it is a wait & see game that we'll all know about in a few months when it is done & run.

Cheers Oz
 
Exceeding the flow capabilties of a head in a drag race cr is common pratice with some guys since they feel the valve is at peak flow twice. This "Trick" is not my idea of a good thing to do in a street engine. And that peak flow trick isn't worth much IMO. But in drag racing, every pony counts.
 
rumblefish360 said:
Exceeding the flow capabilties of a head in a drag race cr is common pratice with some guys since they feel the valve is at peak flow twice. This "Trick" is not my idea of a good thing to do in a street engine. And that peak flow trick isn't worth much IMO. But in drag racing, every pony counts.
Click to expand...

Sounds like you have the same opinion as my head guy & I should stay with what I have got which I am happy to do as I can always change cams later if need be.

Thanks Oz
 
I think everyone is trying to be nice in explaining the same thing - those heads and that cam are never going to make 500HP.

If you consider it takes 400 HP in a 3500lb car (no driver) with "sensible" gears to make a flat 12, (give or take 20HP) you can see how much off the boil the current combo is.

I recommend you set yourself a HP target and aim for it....plenty of knowedgable folks on here can steer you in required head flow, carbs and cams once thats settled on.
 
Go over 500HP as the engine guy said. I think it might work.
 
Rat Patrol said:
Mikesduster has it right. I don't know of any [email protected] / 230cfm headed 3500lb 10 sec cars.
Click to expand...
241@50 219cfm headed 3200lb 10.90et bigblock duster sound good?
its not mine, its an other members, but its fast.

Hello there OzCuda, hope all is well up your way mate.
Are the heads going to see more porting before they go on the stroker?
Will you stay with the dual plane intake for the new combo?
What size and length are the headers? are they big enough for a stroker?
And does your engine man no you only planning on a 3000rpm converter?
 
241@50 219cfm headed 3200lb 10.90et bigblock duster sound good?
its not mine, its an other members, but its fast.
Click to expand...

Very impressive Tim - but what have you left out? NOS? Turbo? LOL!!

Putting that aside - its still 6 deg more duration and who knows how much more lift, a Big BLock and 300 lbs lighter..possibly more if its with driver.

Perhaps i should have said I don't know of any "[email protected] flat tappet/ .520 lift, 230cfm headed SMALLBLOCK, 3500lb 10 sec cars" :D
 
im no expert, but it your stroker needs better heads and cam to get 550 hp.
 
Ok Guy's found the paperwork the heads flow 256 inlet & 185 ex. We have now decided to rebuild another short motor & use the heads I have .

a few of you seem to be hung up on the HP as I said before I don't really care about HP as long as the times are there I can't even tell tyou what HP we have now as long as we keep moving forward.

Once the engine guy tells me which cam he recommends & has calculated the comp I'll put up another post.

I will also be getting a new stall as the engine will be internally balanced so stall speed may change to suit the cam as needed.

Oz
 
Perhaps i should have said I don't know of any "[email protected] flat tappet/ .520 lift, 230cfm headed SMALLBLOCK, 3500lb 10 sec cars" :D[/QUOTE]

ha ha ha Just bein cheeky RatPatrol, its got the 485 purple shaft and NO no2 or puffer.
Remember Feral tho RatPatrol? He went 11.45 in his full steel Valiant sedan with heads
in the 215-220 range, a wimpy .48-285 adv cam and 443CID, witch is a small BB these days.

Good on ya OZ, Iv helped a few blokes out building there cars on the basis
of a set HP number and they have all been disappointed with there ET's,
aiming for a ET# is the way to go, you'll be far happyer. good luck mate.
 
ha ha ha Just bein cheeky RatPatrol, its got the 485 purple shaft and NO no2 or puffer.
Remember Feral tho RatPatrol? He went 11.45 in his full steel Valiant sedan with heads
in the 215-220 range, a wimpy .48-285 adv cam and 443CID, witch is a small BB these days.
Click to expand...

.5 sec is 50 Hp and he had less weight as well Tim. ;)
 
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