Slant six single, to slant six double.
- Thread starter Cudafishboi
- Start date
-
michiganpat
Well-Known Member
what are you running for a cam in that? something like this is what I'd like to eventually put in my duster with my A833OD/3.23's/27" tall tires...though I am smitten by the Aussiespeed Hurricane long runner manifold....I'd be looking for idle-5000 RPM performance....was originally thinking 2bbl, but a small 4bbl might actually be more economical in cruise with the smaller primaries....not much in the way of progressive 2bbls out there....
Princess Valiant
A.K.A. Rainy Day Auto
Once you get into machining and cams, you're also into a ton of money.
I had the best luck with a stock cast iron 2 barrel manifold and a 2 barrel carb from a 318. Peppy and on the cheap. Slightly improved mpg and way more responsive throttle.
Machining is nice but it's expensive and these days good machine shops are rare so they can charge what they want.
I have seen quite a few 2 barrel setups come up for sure.
I had the best luck with a stock cast iron 2 barrel manifold and a 2 barrel carb from a 318. Peppy and on the cheap. Slightly improved mpg and way more responsive throttle.
Machining is nice but it's expensive and these days good machine shops are rare so they can charge what they want.
I have seen quite a few 2 barrel setups come up for sure.
It is an Oregon Cam SFT regrind, #2106. 214/210 @.050, 444/434 lift, 108 LSA.
Isn't that one of Dutra's reverse grinds?
Correct!
michiganpat
Well-Known Member
what's the theory for less exhaust duration compared to intake duration for the slant? seems counter to pretty much everything you see cam wise nowadays?
I believe he was thinking the intake flowed that well over the exhaust and the exhaust didn't need the extra help. But in testing, they found that those grinds didn't make any more appreciable power than a conventional design. They didn't make less either. At least that's what I've READ. If someone else knows more or something different, please post it.
MidnightSwinger
Well-Known Member
That’s due to the severely limited intake port on the slant. The head was designed for 170 cubic inches with a short stroke, and was originally designed in aluminum. That means huge coolant passages but not a lot of room for porting and reshaping the port before you get into water.
Doug was the forefather of Reverse Dual Pattern cam testing in the slant six world. He swears by them but I haven’t seen anything showing hp gains or losses over a traditional grind.
It does cost, for sure. That's why I do everything I can for machine work here at home. I can enlarge spring pockets, knurl guides as long as they aren't real sloppy, install cam bearings and freeze plugs. I can also check for cracks. I can also do very basic valve jobs if the valves and seats don't need grinding. I've been looking at valve and seat grinders, though.
Then I was thinking the other way around. Thanks.
MidnightSwinger
Well-Known Member
It’s a lot of theory in my opinion but definitely an interesting read. I’ve had a Doug built motor with one of his RDP cams installed and it was a well mannered and sweet running slant!
Yeah. Sometimes the paper doesn't tell the whole story.
Can you share the details on your Dutra motor?
TT5.9mag
Two atmospheres are better than one
Lsa on that cam was 98 installed at 92.
And in later engine masters comps that engine had a 256/264 @050 on a 108 and made a bunch more power, not solely for that reason though. Reverse pattern cams don’t work. That’s why no one uses them anymore.
Here is a rev pattern cam that DID work. 455 Pontiac, 3950 lbs [ without driver ]. 3.31 diff. T400, 2800 stall c'ter. Street radial tyres. Factory Ram Air 4 intake. 236/230 @ 050 cam, 112 LSA, Hi Port Alum heads, 850 TQ carb, smooth idl, headers. Ran 11.78 @ 115 mph.
This was the FIRST TIME the driver had drag raced. No tuning was done at the track such as carb or ign timing adjustments, or different shift rpms. Just drive up to the line & drive....
A later RP cam 254/248 @ 050, with a Victor intake & TQ ran 119 mph. Once again, no trackside tuning & driver had little experience.
This was the FIRST TIME the driver had drag raced. No tuning was done at the track such as carb or ign timing adjustments, or different shift rpms. Just drive up to the line & drive....
A later RP cam 254/248 @ 050, with a Victor intake & TQ ran 119 mph. Once again, no trackside tuning & driver had little experience.
It really is nonsense to claim as a blanket statement that RP cams do not work. In the same EMC contest that Jon Kaase won, post #65, He also had a 429 Ford entry that had a RP cam, 264/256 @ 050. He came 5th out of 29 entries listed in the results in PHR magazine in Feb 2009. His engine recorded the highest hp, 746, of those listed.
A recent trend has been to use lower ratio rockers on the exh. If the cam is a single pattern, you are effectively converting to a RP cam, acknowledging that the extra lift & duration is not needed.
A recent trend has been to use lower ratio rockers on the exh. If the cam is a single pattern, you are effectively converting to a RP cam, acknowledging that the extra lift & duration is not needed.
TT5.9mag
Two atmospheres are better than one
Show me one test, any kind of comparative data where a reverse split was tested against a similar traditional split pattern cam and it makes more power. I’ll wait.
EVERY TIME I’ve seen them tested back to back, the only difference being reverse split vs forward traditional split pattern the forward split makes more power. Not “some” of the time, not “most” of the time, EVERY time. It is really nonsense to claim that they do work better with no comparative data.
MidnightSwinger
Well-Known Member
It’s been a few years but it was a true 9:1, Dutra oiling mods and blueprinted pump, rdp15(?) cam and the head was ported/polished/gasket match. Offy 4 bbl with eddy 500 and OG Dutra duals y’d into a single. Nice bottom end but kinda breathless above 5k.
I don't see his slant 6.
What's nonsense is, you bringin your bullcrap in here when the only engines we were discussing reverse cams on was a SLANT 6. Go take your chit somewhere else.
The answer has been given many times in this thread. Read.
-
Similar threads
- Locked
[FOR SALE]
66 slant six fan and single groove pulley
