371 build W/Big Mouth heads
- Thread starter RAMM
- Start date
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RAMM
Well-Known Member
So so close. Maybe this weekend but probably Wed-Thurs. J.Rob
RAMM
Well-Known Member
Well a little update is in order: Broke the cam in this evening with the outer springs only for a total of 20 mins. No oil leaks which is nice and really nice oil pressure- 40 psi@1000rpm 60-63 psi@ 2500rpm and up hot. Checked lash and nothing out of place there. Tried two exploratory pulls from 3500-4500 and 3800-5000. Wow is this thing cammy--falls into a hole right off the brake and takes off when it hits 4000 rpm like someone hit the N20 button. HP curve is quite steep from what I can see so far.
The plan for tomorrow is install the inner springs and find out what's what. Timing is locked out @ 35 and I can already tell this thing's gonna need a timing curve shaped like a banana.
Very interested to dial this in and if it shows promise I might order another custom cam and install it right on the dyno cart ASAP. J.Rob
The plan for tomorrow is install the inner springs and find out what's what. Timing is locked out @ 35 and I can already tell this thing's gonna need a timing curve shaped like a banana.
Very interested to dial this in and if it shows promise I might order another custom cam and install it right on the dyno cart ASAP. J.Rob
yellow rose
Overnight Sensation
Can you remind me what cam you have now.
Since I'm not spending my money, of course I'm going to say hell yes slap another cam in there whilst you are on the dyno.
When I'm spending your money I spend like a drunken sailor. No offense to all the navy folk out there.
Well, I hope very much that the heads do well in your combo. Best of luck, wishing you well.
dadodgekid
When in doubt... floor it
Awesome! Glad you got it together!
RAMM
Well-Known Member
Thanks and I have to say it went well tonight. Changed the springs. Forgot who I lent my v-spring tool too and had to fab up this one. It didn't work all that well until I learned the technique. J.Rob
RAMM
Well-Known Member
Installed the inner spring and proceeded to put it through another 5 min break in cycle between 1900-2500 rpm. Oil was warm and away we went. This is the 3 rd pull @ 36-37 degrees. I have to say I was more than a little impressed. I think I will order a different cam and really go after driveability and see how close I can get to this kind of power. Before I take this off the dyno I will try a few more things and log things like manifold vacuum, cfm, etc.. Any questions? J.Rob
dadodgekid
When in doubt... floor it
480lb/tq nothing too sneeze at with 3.58 stroke! What was the compression on this mighty sb?
So the big mouth heads are working better than expected?
MOPAROFFICIAL
Oogliboogli
As i said, mid 500's.
Some would have to try hard to screw that up, but I never put it past most average builders. Now the next cam.
RAMM
Well-Known Member
Exactly 11-1, testing was done on Esso 91. Started and shut off excellent with timing locked out at 35-36. J.Rob
RAMM
Well-Known Member
The peak HP number surprised me a bit but the overall torque curve is weak and peaky. Also the overall personality of the engine is crappy or should I say quite racy. Right off the brake it falls into a hole and then recovers slowly if loaded at anything below 4000 rpm--not a good street engine would this make. J.Rob
RAMM
Well-Known Member
Since your crystal ball is so clear right now tell me this: If this intake, heads, and camshaft were bolted onto a 416 short block what would the results be? J.Rob
stixx
Well-Known Member
So this seems to be a success, at least horsepower wise...
And with a big honking SFT and "only" 371 cubes one probably has to put up with the manners below 4000.
But then you said you will try some more tricks.
RAMM
Well-Known Member
So this seems to be a success, at least horsepower wise...
And with a big honking SFT and "only" 371 cubes one probably has to put up with the manners below 4000.
But then you said you will try some more tricks.
Yes I had a benchmark in my mind of 525-530 peak HP and peak TQ of 470-480 to consider this experiment a success.
Planning on trying an advance curve, smaller diameter collector headers, different sparkplugs, carb spacers, and really dialing in the carb. As of right now I have not done a thing other than setting timing @ 36-37 and making sure lash was set @ .018" hot. I haven't even installed air turbine to record air consumption/AFR. My crappy spring compressor tool ate up way too much of my time last night. J.Rob
Do you think the peakiness and torque issues are cam or head related? Or both?
RAMM
Well-Known Member
Both. When it idles @ 1150-1200 rpm it surges like it has a blower on it. Retarded amounts of reversion. J.Rob
Oh wow!!! Wide LSA cam in its future?
RAMM
Well-Known Member
Correct. J.Rob
RAMM, do you think that head is a bit much for the displacement?
Jesse did you do any blending or are these heads the way they came from Hugh's the reason I ask is would the shitty short side help cause the low end power below 4000 you speak of .
B3422w5
Well-Known Member
They designed W2/5 stuff for stock stroke motors.
No eddie type head will ever be too big for a stock stroke smallblock that is making any steam at all.
Modified or not, they are still just a factory replacement head.
Wide LSA cam might or might not look good on the dyno, but i can almost guarantee you any car its put in will be a dog out of the gate. Been there done that with 112 stuff in a smallblock drag car that isnt a lightweight gutted ride
No eddie type head will ever be too big for a stock stroke smallblock that is making any steam at all.
Modified or not, they are still just a factory replacement head.
Wide LSA cam might or might not look good on the dyno, but i can almost guarantee you any car its put in will be a dog out of the gate. Been there done that with 112 stuff in a smallblock drag car that isnt a lightweight gutted ride
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