3.79 SBM
#1570354
01/28/14 07:56 PM
01/28/14 07:56 PM
|
Joined: Sep 2012
Posts: 1,563
Janesville, WI
SpareParts
OP
pro stock
|
OP
pro stock
Joined: Sep 2012
Posts: 1,563
Janesville, WI
|
So I'm at a point with engines where I have a clean slate but I have a bunch of LA parts around so why not use them right? I've got 340 blocks, nice W2 heads, a few nicely done intakes, and a solid roller. I don't really like the 4" crank, I see too many of them and I enjoy rpm. I think I figured out a rod and piston combo to work with the 3.79 so that should be fun. Is there any notching required to clear the 3.79 crank in a stock block? Any other combos out there I can compare notes with? (I'm bored and it's -20 out) 
|
|
|
Re: 3.79 SBM
[Re: SpareParts]
#1570355
01/28/14 08:27 PM
01/28/14 08:27 PM
|
Joined: Jan 2003
Posts: 11,733
Portage,michigan
B3422W5
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 11,733
Portage,michigan
|
I have seen many 4 inch motors( including one I ran for year's) turn 7500 all the time. A good crank isn't going to be the major rpm limiter anyhow. Light piston/rod and quality valve train gear are mighty important. Last I knew 3.79 Mopar cranks are 1053 forgings, not the better 4340. But maybe there are other suppliers now. With W2 heads and a good bit longer than factory stroke crank, unless you are building something mighty exotic, I don't think running non killer rpm is a bad thing at all , nor do I see any use for it with those heads and either crank.  ,
Last edited by B3422W5; 01/28/14 08:29 PM.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight
418 BPE factory replacement headed stroker, 565 lift solid cam, footbrake street/strip car
Best so far, 10.32 1/4
1.41 best 60 foot
6.56 at 104.17
|
|
|
Re: 3.79 SBM
[Re: B3422W5]
#1570357
01/28/14 08:38 PM
01/28/14 08:38 PM
|
Joined: Sep 2012
Posts: 1,563
Janesville, WI
SpareParts
OP
pro stock
|
OP
pro stock
Joined: Sep 2012
Posts: 1,563
Janesville, WI
|
Looking at a K1 or Molnar crank. Just doing a fun build. The cranks are 4340. I would think the thing should make decent power, the heads flow well.
I suppose I should add I use nitrous.
Last edited by SpareParts; 01/28/14 08:44 PM.
|
|
|
Re: 3.79 SBM
[Re: MR_P_BODY]
#1570358
01/28/14 11:10 PM
01/28/14 11:10 PM
|
Joined: Jan 2003
Posts: 2,155
Tucson, Arizona
clonestocker
top fuel
|
top fuel
Joined: Jan 2003
Posts: 2,155
Tucson, Arizona
|
Quote:
Quote:
So I'm at a point with engines where I have a clean slate but I have a bunch of LA parts around so why not use them right?
I've got 340 blocks, nice W2 heads, a few nicely done intakes, and a solid roller. I don't really like the 4" crank, I see too many of them and I enjoy rpm. I think I figured out a rod and piston combo to work with the 3.79 so that should be fun.
Is there any notching required to clear the 3.79 crank in a stock block? Any other combos out there I can compare notes with?
(I'm bored and it's -20 out)
with the 3.79 you dont need to notch the bores...
most of my engines are 3.79 but the Rampage has a
4.0 for the added torque... if you like rpm then yes
go with the 3.79... my 405 turns 8200-8300 rpm...
my 395 turns 8100 rpm... both with about 5600 stall
EDIT
you don't need to notch unless you run alum rods(and
I don't know that for fact) I run Eagle H-beams in
all my SB engines
Not to steal the thread but my motor combo is 4.125 x 3.79. Killer potential I think. But here's my question. Mike, you're talking huge RPM. I shift mine at 7,000 rpm and cross the stripe at 5,800 RPM. Tall tires not enough gear and a small carb (750). What kind of improvement in ET do you think could happen by putting a bunch of tail gear in the car and a 1050?
[img] [/img]
|
|
|
Re: 3.79 SBM
[Re: MR_P_BODY]
#1570360
01/29/14 12:15 AM
01/29/14 12:15 AM
|
Joined: Oct 2009
Posts: 1,267
North, Alabama
D-50
pro stock
|
pro stock
Joined: Oct 2009
Posts: 1,267
North, Alabama
|
Mr. P BODY what does your car weight? I am running a 3.79 stroke also and was wondering if I should shift at a higher RPM. I have been running a 950 carb and shifting at 6800 and crossing the line 66-6800 with a 5.13 gear. I am in the process of upgrading my fuel system from a carter mechanical pump and 3/8 fuel line to a Magnafuel pump, -10 line and a 1050 dom. that it was dynoed with.
I run 1/8 mile and I broke the 5.13's and need to decide what gear ratio to replace them with. I am running 315/60 drag radials that are 30 in. tall and weight 2950 with 5400 stall. Mine is also ran on 93 octane if that makes any difference.
Sorry for the hijack....
1.33 60 ft,6.21 at 110.59 in the 1/8, pump gas small block,2950lbs,drag radials,mufflers and driven to track ...
|
|
|
Re: 3.79 SBM
[Re: D-50]
#1570361
01/29/14 12:29 AM
01/29/14 12:29 AM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
Mr. P BODY what does your car weight? I am running a 3.79 stroke also and was wondering if I should shift at a higher RPM. I have been running a 950 carb and shifting at 6800 and crossing the line 66-6800 with a 5.13 gear. I am in the process of upgrading my fuel system from a carter mechanical pump and 3/8 fuel line to a Magnafuel pump, -10 line and a 1050 dom. that it was dynoed with.
I run 1/8 mile and I broke the 5.13's and need to decide what gear ratio to replace them with. I am running 315/60 drag radials that are 30 in. tall and weight 2950 with 5400 stall. Mine is also ran on 93 octane if that makes any difference.
Sorry for the hijack....
Mine is 2400# race weight.... it still comes down
to the torque... with a 3.79 we are giving up the
torque so we have to gear it to make up... to me
your 5.13 is barely enough gear(for the 1/8)... the
stall is always dictated by the max torque rpm and
then add a couple hundred rpm for the stall... gear
ratio is for the top end.. gear it to cross the line
at 10% above the peak HP rpm... and yes I run a 727
trans to help it off the line.. with my set up I have
a 1.19 60' best and a 1.21 60' for a normal on used
tires... of course the heads will say what the
rpm will be(along with the cam)
|
|
|
Re: 3.79 SBM
[Re: MR_P_BODY]
#1570362
01/29/14 12:36 AM
01/29/14 12:36 AM
|
Joined: Oct 2009
Posts: 1,267
North, Alabama
D-50
pro stock
|
pro stock
Joined: Oct 2009
Posts: 1,267
North, Alabama
|
Quote:
Quote:
Mr. P BODY what does your car weight? I am running a 3.79 stroke also and was wondering if I should shift at a higher RPM. I have been running a 950 carb and shifting at 6800 and crossing the line 66-6800 with a 5.13 gear. I am in the process of upgrading my fuel system from a carter mechanical pump and 3/8 fuel line to a Magnafuel pump, -10 line and a 1050 dom. that it was dynoed with.
I run 1/8 mile and I broke the 5.13's and need to decide what gear ratio to replace them with. I am running 315/60 drag radials that are 30 in. tall and weight 2950 with 5400 stall. Mine is also ran on 93 octane if that makes any difference.
Sorry for the hijack....
On the Dyno it made peak HP at 7300 and the heads flowed 337@ .650 on Brett Millers bench.
Mine is 2400# race weight.... it still comes down
to the torque... with a 3.79 we are giving up the
torque so we have to gear it to make up... to me
your 5.13 is barely enough gear(for the 1/8)... the
stall is always dictated by the max torque rpm and
then add a couple hundred rpm for the stall... gear
ratio is for the top end.. gear it to cross the line
at 10% above the peak HP rpm... and yes I run a 727
trans to help it off the line.. with my set up I have
a 1.19 60' best and a 1.21 60' for a normal on used
tires... of course the heads will say what the
rpm will be(along with the cam)
1.33 60 ft,6.21 at 110.59 in the 1/8, pump gas small block,2950lbs,drag radials,mufflers and driven to track ...
|
|
|
Re: 3.79 SBM
[Re: D-50]
#1570363
01/29/14 12:38 AM
01/29/14 12:38 AM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
Quote:
Quote:
Mr. P BODY what does your car weight? I am running a 3.79 stroke also and was wondering if I should shift at a higher RPM. I have been running a 950 carb and shifting at 6800 and crossing the line 66-6800 with a 5.13 gear. I am in the process of upgrading my fuel system from a carter mechanical pump and 3/8 fuel line to a Magnafuel pump, -10 line and a 1050 dom. that it was dynoed with.
I run 1/8 mile and I broke the 5.13's and need to decide what gear ratio to replace them with. I am running 315/60 drag radials that are 30 in. tall and weight 2950 with 5400 stall. Mine is also ran on 93 octane if that makes any difference.
Sorry for the hijack....
On the Dyno it made peak HP at 7300 and the heads flowed 337@ .650 on Brett Millers bench.
Mine is 2400# race weight.... it still comes down
to the torque... with a 3.79 we are giving up the
torque so we have to gear it to make up... to me
your 5.13 is barely enough gear(for the 1/8)... the
stall is always dictated by the max torque rpm and
then add a couple hundred rpm for the stall... gear
ratio is for the top end.. gear it to cross the line
at 10% above the peak HP rpm... and yes I run a 727
trans to help it off the line.. with my set up I have
a 1.19 60' best and a 1.21 60' for a normal on used
tires... of course the heads will say what the
rpm will be(along with the cam)
So your giving up power just due to the low rpm
|
|
|
|
|
