All out performance bbc

[evilbanshee]

Hi fellas.

I need too build a all out N/A bbc 427.

flat tappit solid cam.

whats your opinions on a bottom end? rod length, ring packs.

lets assume money isnt a issue.

aluminum rods? 043 ring packs? lightest ringg pack? is 1.88 rod journals possible for bbc applications?

and go..

[Old School]

How may rpm's do you intend to spin it? Are titanium valves considered in this build?

[F-BIRD'88]

ALL OUT:

Forget the flat tappet cam..
Put a roller in it.. Invest in cylinder heads, induction and exhaust. before non stock rod length etc etc..

A 496 will go faster than any 427 bbc..
Its the same block.. Cubes is king.

"All out" on pump gas or on racing gas?

[rebelrouser]

first issue I see is all out build with a flat tappet camshaft. Today's big flat tappet camshafts just don't like to live, they go flat. Others experience may vary but I will not try and build a high HP engine anymore with a flat tappet camshaft. The last ones I did several years ago, got EDM lifters and grooved lifter bores. They did hold up. But I have no doubt a roller camshaft would have made more power, in the same engine. But they were for limited pilling truck class where no roller cams were allowed, they have changed the local rules now.

Next is 454 stuff is al lot more available as far as stroker kits go. No replacement for displacement. Decent bolt together parts can make you 1.5 HP per cubic inches 427 would be 640HP real popular 454 BBC build 496 would be 744 HP big difference for parts that will cost about the same money for a rotating assembly for each engine.

Unless of course this is a class like stock or super stock build, where you have to keep 427 inches.

[69427]

We have run ~6.40's @ 3250 with 13.5cr, roval ports 290cc, injected methanol, and a Bullet flat tappet. (6800) T400

The current combo in my signature (9.42 @ 142) are the same roval ports AFD 370cfm @ .800, and a Bullet roller. (7500)

Crower 6.135 rods, 4.320 J&E custom pistons, 3.76 Scat LW crank T&D.

[lefty o]

not often i totally agree with fbird, but all out, you want a solid roller cam. flat tappet need not apply.

[FC-Pilot]

Okay, if I were doing this I would start with a raised cam and oversized lifters and a 55mm or 60mm cam core. I would use a big bore >4.6” and how ever short of a stroke to make it meet the class requirements. I would use a raised port, shallow valve angle head and have it ported specific to the needs of the combo (no off the shelf stuff). Ti valves, shaft rockers and, and, and…

How much do you want to spend? Are we bench racing or is this for real?

Paul

[SchmidtMotorWorks]

That depends on what "All Out" means.

What is the reason for the small displacement and flat cam?
Is it part of a rules package?

If you are not restricted to rules, you might consider a more modern platform such as an LT.

[Geoff2]

BBC have a 1.7 rocker & large valves. Both require strong springs for valvetrain control. FT cams do not like or last long with strong springs....

[evilbanshee]

has too be flat tappet. has too be a 427 platform.

titanoum valves is a option.

so what rod? ring pack?

spinning it too 7500. maybe 8000 at most.

gm heads, block, dual plane intake are being used. because i have too.

[Dave Koehler]

An all out engine with oem parts. Seems a trifle contradictory.
Exactly what are the rules? Exactly

[swampbuggy]

Dave....your sentences / responses are always dead on !

[rustbucket79]

has too be flat tappet. has too be a 427 platform.

titanoum valves is a option.

so what rod? ring pack?

spinning it too 7500. maybe 8000 at most.

gm heads, block, dual plane intake are being used. because i have too.

Realistically the factory L 88 short block worked in untold numbers of bracket engines for many years without issue.

Virtually any quality aftermarket steel rod will work, I would consider a longer rod just to reduce the piston weight.

95% of the effort should go towards the heads, intake, and camshaft.

[SchmidtMotorWorks]

has too be flat tappet. has too be a 427 platform.

titanoum valves is a option.

so what rod? ring pack?

spinning it too 7500. maybe 8000 at most.

gm heads, block, dual plane intake are being used. because i have too.

If you can run an LT, do so, it has decades of design evolution in the stock design.

[evilbanshee]

well i was thinking 13:1. 6.385 long rods.

anyone ever done a 1.88 rod journal in a bbc?

or low tension oil rings?