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Biomedtechguy 572 Bill Mitchell aluminum RB block build thread and other stuff...

biomedtechguy

biomedtechguy

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I figured I'd start a build thread on my Bill Mitchell aluminum RB (big bore 4.50") block, and I may throw in some chassis and traction aids stuff along the way, along with the Nitrous Express 6bbl N²O system if and when that time comes. I am having it gapped for up to a 350HP shot.
To kick it off, I'm posting my full cam specs that I needed some info from for B3E to get the T&D rocker arms tweaked for valvetrain geometry correction on the up to .700 lift TrickFlow 270 heads.
Here it is, comments welcome.
Screenshot_20220617-110106_Outlook.jpg
 
If you're going to build an aluminum block 572" why are you using TF 270 heads? Those will not even begin to feed that size engine for much more than a mild street engine.

Tom
 
PROSTOCKTOM said:
If you're going to build an aluminum block 572" why are you using TF 270 heads? Those will not even begin to feed that size engine for much more than a mild street engine.

Tom
Click to expand...
Because I am likely going to be using my Roadrunner in a similar manner as I have for years, albeit with some shift towards more track time, about 70-80% street.
Mild? 6XX HP and 700ft lbs torque is my goal.
The only "better" head I can think of for dual duty is the Indy 572-13 and they have a rather high buy in. Also, I'm going to start with a ModMan intake and the Promax modded 6bbl Holley carbs. If I need more air/fuel than they can possibly deliver, my next look would be a 3x2 throttle body direct port injection setup from F&B.
 
PROSTOCKTOM said:
If you're going to build an aluminum block 572" why are you using TF 270 heads? Those will not even begin to feed that size engine for much more than a mild street engine.

Tom
Click to expand...
Really? Oh never mind.
 
@IQ52
Please give me your thoughts on the cam specs. It's your haunting admonition against hydraulic rollers that coerced me into solid rollers w/EDM.
:thumbsup: :lol: :thankyou:
 
I think it will drive around on the street meekly, i.e. strength under control. Remember the 4.125 stroke small block with a similar cam to yours made 572 lb-ft and 629 hp with cylinder heads that only flowed 300 cfm. It was pleasant to drive around town with 3.23 gears and a manual shift 727 using 3rd gear only. Better have it pointed straight when you pull the trigger.
 
IQ52 said:
It was pleasant to drive around town with 3.23 gears and a manual shift 727 using 3rd gear only. Better have it pointed straight when you pull the trigger.
Click to expand...
Well...If 3.23 gears were "pleasant" to drive around town in 3rd gear w/an automatic, my 4.10 gears will be like having a hair trigger. The 855 5 speed allowed me to "go there" from my 3.54s, but 5th w/the 4.10s are 750 RPM less than 4th was with the 3.54s.
Your last sentence made me smile, in a devious kinda way...
Thanks buddy.
 
dvw said:
Why only 1.5 rockers?
Doug
Click to expand...
My builder must have a reason.
I'm getting the rockers from Michael Beachel at B3E, his "tweaked" T&D #8260 and I just forwarded the cam specs he needed (lobe lift and hot lash) so I could ask him. I guess .640/.645 with the TF270s made for .700 lift was a good combo? Remember, I'm starting with and hoping to stay with my Promax modded 6bbl Holley carbs, in deference to the "V" in my VIN# and I love a 6bbl. Honestly, although I am pretty sure my "step up" would be a high flow 3x2 TB/DPI setup from Bruce at F&B, the only other thing I'd think of is a 6bbl "Dominator" setup or 2x4bbls. I like multiple carbs!
The reason why I went 572 vs 541 is neither require clearancing and I would have used an external oil pickup either way, and the Molnar crank costs the same, and I figure extra cubes can't hurt big, fat torque goals.
 
I guess 1.5 rockers to keep the springs that come on those heads away from coil bind, I thought 1.6's were the order of the day tbh which would be .680-ish lift with the B3 stuff, I think you lose a bit of lift with those?, that would probably require different springs.

So .645-ish lift with a 4.5" bore should net you around 350cfm from TF's quoted no's which is around what we [email protected]" lash adjusted with our. 572-13's and 1.55 Jesel's according to some calcs I did for cfm/hp/et etc.

All in all the 2 motors are very similar, I would think you have a bit more comp than us (10.5:1?) and a lot more carb so 700+hp/700+ftlbs should show on the dyno, both good street/strip motors. Talked to my mate at the last race meeting, he said he gave it some right foot on the street but won't do it again in a hurry, and thats with a tight street verter as well, perhaps with some DOT race tyres but not on pure street tyres!. You'll have to post the numbers up Bio.
 
CR is somewhere in the 10.X range, I'm not certain, but Diamond pistons are paid for and ordered.
Yeah, 700HP/700TQ would require surgery to remove my grin.
 
440rb said:
I thought 1.6's were the order of the day tbh which would be .680-ish lift with the B3 stuff, I think you lose a bit of lift with those?, that would probably require different springs.
Click to expand...
From Michael:
"My rockers are different than the T&D 8260, and account for the relocated shaft, which the 8260 does not. I need the specs to determine the exact amount of relocation needed".
He knows what I'm using, so I have to believe it will all work together.
I WILL ask about rocker arms ratio since I'm getting them from B3E.
The cam specs came from my builder. If the rocker arms from B3E have a higher ratio, I'll ask how that affects lift and the "up to .700" lift" springs
 
Last edited:
Anyone using or has 1st hand experience with a 4 speed +OD transmission that can handle the kind of power I'm going to be making?
I'm starting with the Passon 855. Jamie Passon has expressed confidence in the 700 continuous ft lbs torque rating, calling it "conservative".
BUT
Our very own @weedburner whose fine manual clutch "bite" launch/shift controllers I'm a fan of, having the hydraulic throwout bearing based HitMaster myself (and unfortunately not the time, yet, to try it out and tune it in) posted an eye opening (and alarming) post on how much power the flywheel and pressure plate store. I was only considering the engine torque, but the weight of those rotating masses store energy.
If my 855 breaks, I'll put my 18 spline 833 in to get by, and send the 855 off for repair, but at that point I'd be looking for a manual transmission that could handle the job.
Jericho and G-Force are all I can think of, but I'm sure there are others.
:popcorn2::popcorn2::thankyou:
 
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