Mopar Action 408 Build

-
W

Wilson

Well-Known Member
Joined
Jun 12, 2015
Messages
52
Reaction score
21
Location
Taunton Ma
So for the last 2 issues, MA is featuring a 408 build based on a cheap Ebay-sourced '90 fact. roller short block, Trick Flow heads, and a mild custom roller Bullet cam-.516 lift and avg. 240 @ .050. What I found interesting is their use of stock stamped steel rockers w/ custom length pushrods to set the preload. The rest is stock hydro. roller lifters/dogbones and the stock "spider" retainer. I'm in the 408 planning stages and their intended usage is similar to mine (4-speed, 3.23, similar weight car), and I could see myself building something like this although with better parts in the short block and more comp. as their combo. is at 9.66. I have no experience with any roller stuff and would like some opinions on the durability and suitability of the fact. parts for a street performance application. Would the stamped rockers negate the need for any possible geometry correction? The article implies that the LA roller and Magnum lifters, retainers, etc. are the same. True? Thoughts on this build vs. an older block w/ SFT cam?
 
I'm not sure what part of the engine you are worried about for durability, but would NEVER use a stock rocker on that head. EVER. Trick Flow relocated that rocker shaft saddles on that head and I'm waiting to see what the geometry looks like with that rocker.

Buy a good rocker, like the PRW stainless rocker and contact Mike at B3 racing engines to get his geometry correction kit. Read all the tech articles on his webpage. He also sells the rockers.
 
yellow rose said:
I'm not sure what part of the engine you are worried about for durability.
Click to expand...
Yeah, could have phrased that better. Thought i read somewhere about the chamfer on top of lifter bore and it's varying size, and possible oiling issues w/ hi lift cams. Maybe that was only with retrofit roller lifters in non-roller blocks. Specifically, would there be any issues running lets say a.550ish lift cam in a 360 roller block using all fact. hydro. lifters/link bars/spider, and aftermarket rockers with proper geometry? I assume these would have come with a fact. cam w/ lift no higher than the low .400's, in trucks and vans.
 
Wilson said:
Yeah, could have phrased that better. Thought i read somewhere about the chamfer on top of lifter bore and it's varying size, and possible oiling issues w/ hi lift cams. Maybe that was only with retrofit roller lifters in non-roller blocks. Specifically, would there be any issues running lets say a.550ish lift cam in a 360 roller block using all fact. hydro. lifters/link bars/spider, and aftermarket rockers with proper geometry? I assume these would have come with a fact. cam w/ lift no higher than the low .400's, in trucks and vans.
Click to expand...
No issues at all, my 89 roller LA block 408 W2 engine is .580 lift with 1.6 rockers. The factory roller stuff works great and is very reliable.
 
yr is correct about the rocker shaft relocation
the stock LA rockers have a big wear radius so that part would work if the shaft was just moved back
not so much if they are moved up-unless they are using longer valves (which is a really great idea) as well as smaller dia stems
so you have to check the geometry
try a stock rocker and a 273 style iron rocker and map the dykem pattern on top of the valve
open, mid lift and closed with your valve lift
looks like they picked a master with the nose rolled over- lift limited- maybe to avoid contact with the keepers/ retainers and the stem seals or to make the use of stock rockers possible
one known problem with stock rockers is pushing the pushrod through the rocker with spring pressure and rpm but I've run stock rockers with more lift than that when I had to
what springs are they recommending- similar to stock roller springs? post up the spring pressures
if you run hollow pushrods and the lifters have oiling that would help with the pushrod/ rocker wear
If you go roller tip rockers you will need a b3 kit
that was the long answer
short answer is to ask B3 and do whatever he tells you
me- i'd mock it up with the degree wheel and dial indicator etc
do those heads use LA stock length valves or long valves
is the spring height stock or do you have room for some better springs
what's your stem seal clearance
spring locators
measure twice- cut once
 
i posted this before…..this is at .373" lobe lift, so lift wise there should be absolutely no Trouble. Even .400" lobe lift is not pushing it, with the stock base circle of the cam. Pretty interested what they can achieve with the TF Heads! Any Information about the cams LSA?

Michael
20190117_173728.jpg
 
360duster said:
Pretty interested what they can achieve with the TF Heads! Any Information about the cams LSA?
Click to expand...
Cam specs: .516/.516, 291/295; 237/241@.050, in @107
Timing events @.050 11.5 45.5 53.5 7.5
Article mentions they're thinking about 500 crank HP
Seems optimistic with 9.7 comp. and an Action+ intake
 
Wilson said:
Cam specs: .516/.516, 291/295; 237/241@.050, in @107
Timing events @.050 11.5 45.5 53.5 7.5
Article mentions they're thinking about 500 crank HP
Seems optimistic with 9.7 comp. and an Action+ intake
Click to expand...

Which of the TF heads are they running? Is it the ones the the weakest springs? I know when I talked to TF they said that some builders were using the those heads with success on lower lift rollers cams.
 
custom or a grinder that has different intake and exhaust lobes
sure does make setting up the springs easier
 
Wilson said:
Cam specs: .516/.516, 291/295; 237/241@.050, in @107
Timing events @.050 11.5 45.5 53.5 7.5
Article mentions they're thinking about 500 crank HP
Seems optimistic with 9.7 comp. and an Action+ intake
Click to expand...

ok, so you mean installed at 107° Intake Centerline....what LSA does it have? Is there a link to the Story?

thanks, Michael
 
360duster said:
ok, so you mean installed at 107° Intake Centerline....what LSA does it have? Is there a link to the Story?

thanks, Michael
Click to expand...
No link as it wasn't online; the articles are featured in the last two issues of Mopar Action, Nov./Dec. and Jan/Feb. I believe they are. No part # was given for the heads, nor was any mention of the springs made, or what springs Bullet recommended. No mention of the cams LSA either.
 
Wilson said:
Cam specs: .516/.516, 291/295; 237/241@.050, in @107
Timing events @.050 11.5 45.5 53.5 7.5
Article mentions they're thinking about 500 crank HP
Seems optimistic with 9.7 comp. and an Action+ intake
Click to expand...

Ehrenberg also mentioned using 340 cast iron exhaust manifolds too. Those stamped rockers he's using probably have an actual ratio closer to 1.4 to 1. That will really hurt lift at the valve. I would guess he'll be closer to 400 HP at the crank.
 
lot of duration for that lift
maybe they rolled the nose over- limited lift - for springs reliability, other reasons
you'd have to graft the "area under the curve"
 
The timing events are listed...... just get out your calculator.

(Looks like it’s a 110lsa +3)
 
timing events at .050 are useless for determining dynamic compression or even seat timing
long ramp cams like stock mopars are particularly deceptive
 
4wd dyno.

If you have a 4wd dyno, and can’t uncouple the front rollers, then there is power wasted by the rear rollers having to use power to also turn the front rollers(through the coupling mechanism), and the front wheels/tires.
 
Wilson said:
Cam specs: .516/.516, 291/295; 237/241@.050, in @107
Timing events @.050 11.5 45.5 53.5 7.5
Article mentions they're thinking about 500 crank HP
Seems optimistic with 9.7 comp. and an Action+ intake
Click to expand...
Can you post a link to the article?
 
You must log in or register to reply here.
-

Back
Top