mguner
How many is too many?
I'd set them at .018 and .026 and see if the bottom end comes back some. It should. That cam is a bit much for your converter. The old heads obviously had better port velocity to help compensate for other inequities.
Dissapointing performance
- Thread starter Dusterguy
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You seem to have all the answers as to what it's NOT, yet you don't know what it IS. I find that humorous, actually.
o1heavy
1974 dart sport
360 with a 600cfm carb little exhaust and highway gears little convertor and a a solid cam
Equals a slow car
What where the timeslips
Before and after
Put in a 4.10 and a 750 mechanical
Secondaries
The 360 will make some power
Equals a slow car
What where the timeslips
Before and after
Put in a 4.10 and a 750 mechanical
Secondaries
The 360 will make some power
GeorgeH
Well-Known Member
Was referring to stall speed not lock-up function
I have set what comp cams advice is. Cant remember it.
These RHS have smaller intake cc than my old heads. These RHS heads looks almost too small from pushrod pinch area. They also have 10 times more better looking exhaust ports. and multi angle valvejob that I didnt have in old heads.
Sorry I dont read your post anymore. Go away If you dont have anything to say.
Count on it.
mguner
How many is too many?
If you don't have an X or H pipe adding one will also help your problem.
justinp61
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Yes your converter and rear gears will affect you're trap speed. If it can't get moving off the line it will not show it's potential. BTW the carb and exhaust are to small for that combo and your gears and converter are wrong too. If you're dead set on the gears and converter put a smaller cam in, you'll be much happier. The heads picked up almost 2 mph so it is making more power than before.
BTW where is your initial timing? With that cam it should be 18-22°.
BTW where is your initial timing? With that cam it should be 18-22°.
o1heavy
1974 dart sport
What did it run
Maybe your old heads didn't have as bad of a port job as you thought, old heads can be ported to stock rhs heads flow numbers and higher.
You could use more gear and stall and carb and exhaust but if you can't do burn outs there must be something wrong with your tune or car mechanically. Just cause everything worked before the swap doesn't mean it can't fail or changed once put back together.
Go through everything and make sure it's in working order and tuned.
You could use more gear and stall and carb and exhaust but if you can't do burn outs there must be something wrong with your tune or car mechanically. Just cause everything worked before the swap doesn't mean it can't fail or changed once put back together.
Go through everything and make sure it's in working order and tuned.
GeorgeH
Well-Known Member
Yup, much improved heads and no gains ,again, indicates the bottleneck is elsewhere. Even Comp Cams recommends 3.91-4.10 gears and a 2100-3100 stall for use with that cam.
Maybe few h
20 is my idle timing. Im not going backwards in cam maybe I do these upgrades what you succest me to do. 2 mph better equals something like 20 hp. I was hoping more I dynoed my old engine and it was 300 hp with smaller cam, old heads and 8.4 compression ratio.
SLOPAR72
Well-Known Member
Vacuum at Idle? Gotta start somewhere. Compression each cylinder? Have you leaked the motor down? Get all the easy stuff out of the way before you jump to any big conclusions.....
better heads? These flow 270 cfm and are high velocity heads. I thought that these are best heads what you can buy for street use.
mguner
How many is too many?
Not a maybe... It WILL.
racerdan80
Well-Known Member
And those are heads are being choked by too small a carb and exhaust. Need at least 1000 rpm stall higher. Do a search of dyno builds with those heads. Imm engines has links to hot rod magazine covering some of their builds and see what they used for carb and exhaust
It is in "stock" location what comp cams says it should be (if you meant intake centerline) I bellieve it can detonate if advanced too much.
SLOPAR72
Well-Known Member
20 something inches with that camshaft??????? You sure about that..... Leakdown check will tell you overall condition of each cylinder and how well you are sealed up. Youtube will be your friend for this.....
I always suggest doing these simple test before getting too excited about what you have going on..... There are a couple of things about your combo that doesn't excite me but as said make sure what you have is sealed up....
JW
Lustle
Well-Known Member
Well. It seems like you don't really want help. But I'm a sucker for punishment. So here it goes.
Yes, the exhaust is all wrong. And YES exhaust contributes A LOT to your power loss.
Congrats. You've put an exhaust on there that can support a whopping 289 horse. What did you say you thought you ran at the track again? Oh right, about 300 horse. Put those headers to work and put on at least a 2-1/2 inch system.
Carb is wayyyy to small. 750 double pumper fits the bill nicely on something like this. Don't use a vacuum secondary on a car that has greater than 230@50 duration cam.
Piston to head clearance. How did you measure that? If your quench is actually .078, I would try and get it down. the .040 area is great.
Once you do all that. Re-tune and re-time. It will need it.
BTW this is the definition of mismatched combo. Hence why it's a dog.
Oh and try to be decent to other people on here that are offering help and such. We are here to help but not when you give us **** attitude in response.
Yes, the exhaust is all wrong. And YES exhaust contributes A LOT to your power loss.
Congrats. You've put an exhaust on there that can support a whopping 289 horse. What did you say you thought you ran at the track again? Oh right, about 300 horse. Put those headers to work and put on at least a 2-1/2 inch system.
Carb is wayyyy to small. 750 double pumper fits the bill nicely on something like this. Don't use a vacuum secondary on a car that has greater than 230@50 duration cam.
Piston to head clearance. How did you measure that? If your quench is actually .078, I would try and get it down. the .040 area is great.
Once you do all that. Re-tune and re-time. It will need it.
BTW this is the definition of mismatched combo. Hence why it's a dog.
Oh and try to be decent to other people on here that are offering help and such. We are here to help but not when you give us **** attitude in response.
racerdan80
Well-Known Member
Is this drag race only? If more street than race i'd say dual plane. Race, single plane. Exhaust, 2.5-3" with x or h pipe to help scavenge and balance out the exhaust. Need more stall on converter. I have personally seen a second or two difference in et's at the track when a matched converter was installed in lieu of a factory tight one which did not compliment the rest of the drivetrain combo
straightlinespeed
Sometimes I pretend to be normal
Im with what every one has told you so far. Listen to these guys and be open minded to what they have to say. Just because you spent money on heads doesnt mean its going to fix your combo, if it is not set up correctly. I for one am with the people that said you have to low of a stall converter.
Here is my set up for a reference.
LA360
Stock Magnum heads
XE268H cam
Air gap
750 carb
TTI's to 2.5" to 2.25" exhaust. Soon to be changed to 2.5" all the way
18* initial 34 total
9.5 SCR
14Hg.
My engine put down 380 on the dyno.
Now in the car Im running a 2800 stall converter and 3:23 gears. I can light the tires up for a block or more. I've even been playing around with a 600 cfm Eddy carb and I can still light the tires up for a block or more. Did I loose some horsepower, Im sure I did, but how often am I going to be driving in the 5200rpm range?
Here is my set up for a reference.
LA360
Stock Magnum heads
XE268H cam
Air gap
750 carb
TTI's to 2.5" to 2.25" exhaust. Soon to be changed to 2.5" all the way
18* initial 34 total
9.5 SCR
14Hg.
My engine put down 380 on the dyno.
Now in the car Im running a 2800 stall converter and 3:23 gears. I can light the tires up for a block or more. I've even been playing around with a 600 cfm Eddy carb and I can still light the tires up for a block or more. Did I loose some horsepower, Im sure I did, but how often am I going to be driving in the 5200rpm range?
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