340 Build- rocker questions

[madhatta360]

Looking for some incite and suggestions on going with 1.5 or 1.6 rockers to give a little extra lift to my current cam since I’ll be updating to speedmaster heads, 2.02/1.6 65cc port/polish, machine for larger pushrod/clearances to accommodate 1.6’s. Looking at using Hughes Engines rockers.

Planning to use .040 Felpro 1008 head gaskets

Cam- Crane 150062
3,000-6,000
228int/228exh @ .050
.480int/.480exh lift factory ratio
112 LSA
Speed pro forged pistons, .030 over
Slightly above deck
Eddy air gap
3.55 suregrip
4spd
Hedman LT headers

 

[Oldmanmopar]

1.6 give better pushrod angle. Moves the pushrod closer to the rocker shaft

 

[12many]

I’d be inclined to use the Mancini 1.6 rocker kit, made for Mancini
by Harland Sharp. Either with pushrods:

Mancini Racing - Roller Rocker Arm & Pushrod Pkg




Or without:

Mancini Racing Aluminum Roller, 1.6 Ratio

The 1.6 will be natural finish, red is 1.5

 

[Rat Bastid]

Looking for some incite and suggestions on going with 1.5 or 1.6 rockers to give a little extra lift to my current cam since I’ll be updating to speedmaster heads, 2.02/1.6 65cc port/polish, machine for larger pushrod/clearances to accommodate 1.6’s. Looking at using Hughes Engines rockers.

Planning to use .040 Felpro 1008 head gaskets

Cam- Crane 150062
3,000-6,000
228int/228exh @ .050
.480int/.480exh lift factory ratio
112 LSA
Speed pro forged pistons, .030 over
Slightly above deck
Eddy air gap
3.55 suregrip
4spd
Hedman LT headers

I would look around on line and find some cam math and then pick a different cam.

One of the best books for math of that sort is “The Horsepower Chain” by Don Terrell.

Its 80 bucks and AFAIK you can only get it through speedtalk.com unless you can find a used copy.

Im just not into that cam.

 

[mgoblue9798]

Looking for some incite and suggestions on going with 1.5 or 1.6 rockers to give a little extra lift to my current cam since I’ll be updating to speedmaster heads, 2.02/1.6 65cc port/polish, machine for larger pushrod/clearances to accommodate 1.6’s. Looking at using Hughes Engines rockers.

Planning to use .040 Felpro 1008 head gaskets

Cam- Crane 150062
3,000-6,000
228int/228exh @ .050
.480int/.480exh lift factory ratio
112 LSA
Speed pro forged pistons, .030 over
Slightly above deck
Eddy air gap
3.55 suregrip
4spd
Hedman LT headers

Like already mentioned I would seriously consider a cam swap since you are swapping heads anyway.

You can get more lift and better street manners at the same @.050 duration.

Check out Hughes, Comp mopar grinds, or Mike Jones for one of his grinds.

 

[AJ/FormS]

I agree wuth RAT and others to finf a better cam. I would never install a 112 cam into any SBM; the single exception being that I had to get rid of some cylinder pressure, cuz they do that pretty well...... lol.
And [email protected] is a pretty good size, if a lil big for 3.55s. IMO I think you would like better one size smaller at least, with those 3.55s. And for street I would be inclined to choose a dual-pattern cam cuz you can move it around some without giving up the Overlap cycle. Ima thinking a 108 or less LSa.
With alloy heads you need to run the cylinder pressure up, just to break even.
I would just get a hi-lift cam in the first place.
With 3.55s you cannot afford to give up any bottom-end torque. Well you can but I fought it for years and years.

 

[Oldmanmopar]

I just asked my son about the Mancini's and pushrods. We have a big cubic inch race motor here for a refresh . 2 seasons and they are still in very good shape. Mancini would be a good choice .

 

[12many]

I’d do an Isky 274 Mega on a 107 LSA (their oval track Mega version) and those 1.6 ratio rockers. No fast rate for me.

Part# 390174

274° Adv
226°@.050”
.326” Lobe
.490” (1.5 rockers)
.522” (1.6 rockers)
107° LSA
60° Overlap

Yeah, an Isky Cam from the Camfather.....
Get one while he’s still around!

 

[rumblefish360]

With more overlap and a narrower LSA, the idle quality will drop some but the torque will soar! This is not a big deal at all. A 340 with 2.02 intake will work out to be a 108.85, 1.88 valves would be a 107.42 LSA.

A cam @ 228@050 with 3.55’s has been done for a long long time. It was about they typical build done back in the &0’s for that basic hot rodded engine. I wouldn’t go to larger on a tire diameter. 26/27 inches would be fine.

 

[Bewy]

Agree, Isky cam is best for a shelf grind.

 

[Bakerlite]

With more overlap and a narrower LSA, the idle quality will drop some but the torque will soar! This is not a big deal at all. A 340 with 2.02 intake will work out to be a 108.85, 1.88 valves would be a 107.42 LSA.

A cam @ 228@050 with 3.55’s has been done for a long long time. It was about they typical build done back in the &0’s for that basic hot rodded engine. I wouldn’t go to larger on a tire diameter. 26/27 inches would be fine.

22ish@50 and .500ish lift. Just about every cam grinder made one. lol.

 

[rumblefish360]

22ish@50 and .500ish lift. Just about every cam grinder made one. lol.

I’m not sure what to make of this comment except to say “YEP!”
I just remember that it was a super popular route when I was younger. Typical GM guy’s were predictable.
Drive train - 350/350/3.55’s.
Engine build - 10-1, .030-350, 230@050 cam etc…
As AJ mentioned it was a bit of cam in his opinion. I was just stating it’s an old recipe and an often used cam. (230@050.)

Like AJ, I myself of late use a slightly smaller cam @050 and still have really good, if not better results. (IMO, it’s better cam profiles that are available today and nicer cylinder heads for sure.)

 

[Bakerlite]

I’m not sure what to make of this comment except to say “YEP!”
I just remember that it was a super popular route when I was younger. Typical GM guy’s were predictable.
Drive train - 350/350/3.55’s.
Engine build - 10-1, .030-350, 230@050 cam etc…
As AJ mentioned it was a bit of cam in his opinion. I was just stating it’s an old recipe and an often used cam. (230@050.)

Like AJ, I myself of late use a slightly smaller cam @050 and still have really good, if not better results. (IMO, it’s better cam profiles that are available today and nicer cylinder heads for sure.)

I remember the first hot cam I put in a 308 ci engine I had when I was a kid was a brown box special. From memory, it was 224@50 and .496 lift.
Lol, I thought it was so cool.

 

[rumblefish360]

Sounds cool to me. 224@050 is an excellent street driving duration and the lift is good too!