Serious 340 build into 361 HiRPM Screamer

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Emphasis will be put on friction reduction, machining accuracy, induction balance/speedstability with the maximum required flow level of about 270cfm, cylinder pressure, oil control, and valvetrain stability. Looking to for a static compression of 10.8-11.0. Planning on using piston, valve, chamber, coatings as well as oil shedding coatings in the crankcase.

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Just curious here, why are you going with roller tip rocker arms rather than ductile iron? Wouldn't eliminating that be beneficial in reducing valvetrain mass and complexity? Also wouldn't that reduce costs and potential points of failure for what is going to be a street motor?
 
Who makes ductile rocker arms? Thanks know Crane (IIRC) did but not anymore. There were priced right.
I don’t see a complexity issue. I see it the same really. The only other possible point of a failure would be the roller tip. It takes a lot of slamming from excessive lash to break a roller tip axle or otherwise spread the rocker arm tip out enough for a problem.
 
Who makes ductile rocker arms? Thanks know Crane (IIRC) did but not anymore. There were priced right.
I don’t see a complexity issue. I see it the same really. The only other possible point of a failure would be the roller tip. It takes a lot of slamming from excessive lash to break a roller tip axle or otherwise spread the rocker arm tip out enough for a problem.


Mancini Racing - A Engine Adjustable Rocker Arm Set
 
I had this engine come in for a refresh and just happened to notice these axles had partially slid out and were almost making contact with the lifter bores. Imagine the carnage this would have caused. These are short travel Hyd lifters that had .003-.004 preload. First time I see this--it's usually not this subtle. I don't trust 'em . J.Rob

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That right there is why I am going to remove the Comp Retro Hyd rollers out of my 340 this winter. Just praying that they last that long.
Wish me luck.
 
Which shaft mounted ductile iron rockers fit the magnum heads?

Are they available in the desired 1.7 and 1.8 ratios too?
 
I had this engine come in for a refresh and just happened to notice these axles had partially slid out and were almost making contact with the lifter bores. Imagine the carnage this would have caused. These are short travel Hyd lifters that had .003-.004 preload. First time I see this--it's usually not this subtle. I don't trust 'em . J.Rob

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not impressed , now looking at stealing my old 340 back and using the ols style adjustable rockers and non roller lifters
 
Which shaft mounted ductile iron rockers fit the magnum heads?
I never seen mechanical rockers but rollers.
*I Think* I seen them in, ether/or/both/all of them from Jesel, TD & Crower. It was a high end rocker.

Again! *I Think*!

Are they available in the desired 1.7 and 1.8 ratios too?
Not in ductile mechanical, but,
Again I start with *I Think* I seen 1.7. IIRC, *I Think* I seen companies like Comp (but don’t quite me as fact) having a 1.7 rocker. I don’t remember seeing a 1.8 being produced, but if it is possible, it’s only (lots-O-) money the customer has to cough up.

(Sometimes you see so much on the net advertised and what’s new in days, it gets confusing.
 
Horsepower has no effect on rocker life. I truly believe hydraulic roller rockers have their place but not for a motor that see north of 7,000 on a regular basis. A quality hydraulic roller on a stroker that very seldom sees 6,000 RPMs is a whole different animal.lmo
 
So I've taken a full time position with an awesome pipeline company and haven't been getting a lot of time in at the shop but this build is still going forward but with a bit of a twist on the induction side. Since using a pair of inline 600 Holly's on a 572 Hemi I've decided to go with a tunnel ram with a custom welded and machine top to position the aforementioned Holly's on this build. I love tunnel rams and will test with the X-celerator to see how this T-Ram stacks up- should be very interesting. J.Rob

P.S. I am still looking for some genuine TooWoomba cast EQ CH318B's
 
Gonna weld on a 3/8" thick plate on top of this plenum. This was a hideous single four at one time. J.Rob

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That right there is why I am going to remove the Comp Retro Hyd rollers out of my 340 this winter. Just praying that they last that long.
Wish me luck.
what you replacing them with ? i need lifters as well not going to use the hughes roller lifters I have EVEN THOUGH THEY HAVE NOT GONE BAD YET
 
what you replacing them with ? i need lifters as well not going to use the hughes roller lifters I have EVEN THOUGH THEY HAVE NOT GONE BAD YET
Well my Comp junk lifters lasted thru the fall.
Engine comes out tomorrow.
I was lucky enough to purchase a set of solid roller Morel lifters which are made by Callies.
Im hoping at this point that the cam is in good shape.
 
So I've taken a full time position with an awesome pipeline company and haven't been getting a lot of time in at the shop but this build is still going forward but with a bit of a twist on the induction side. Since using a pair of inline 600 Holly's on a 572 Hemi I've decided to go with a tunnel ram with a custom welded and machine top to position the aforementioned Holly's on this build. I love tunnel rams and will test with the X-celerator to see how this T-Ram stacks up- should be very interesting. J.Rob

P.S. I am still looking for some genuine TooWoomba cast EQ CH318B's



first off good luck with the new job. Second where did you work before, did you have your own shop?
 
Well my Comp junk lifters lasted thru the fall.
Engine comes out tomorrow.
I was lucky enough to purchase a set of solid roller Morel lifters which are made by Callies.
Im hoping at this point that the cam is in good shape.
Engines out and top end is apart and off the engine, cam is fine, so the solid rollers are going in.
OBTW you dont have to pull the heads to get the Comp lifters out, at least not with factory X heads.
 
Engines out and top end is apart and off the engine, cam is fine, so the solid rollers are going in.
OBTW you dont have to pull the heads to get the Comp lifters out, at least not with factory X heads.
Edelbrock heads?
 
Edelbrock heads?
Cant help ya, I have no experience
I was told by many people that you must pull the heads to get the tall hyd rollers out. I was able to pull them all out of my LA 340 with the X heads in place.
I did pull the heads to have them ported but thats a different story.
Sorry to hijack the thread
Me bad
 
Edelbrock heads?

On my son's Edelbrock LA heads, on a magnum block, we had to clearance the heads so that the stock magnum roller lifters could go in/ out. We checked this before assembling the motor, just in case he ever needs to change one.

We had milled .030 off of his block, so that may have affected it some.

It was minor clearancing. I actually took pictures, but I don't know if I ever posted them here. The laptop they were on crashed, so I no longer have them.

I have no idea if aftermarket hyd. rollers with the link bars will clear or not.

My Crane solid rollers clear by a mile.
 
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7,000-7,500 is pretty normal for a 340. Shoot for 8,000! lol
 
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