AFR335 Headed 540 on the dyno today....

grumpyvette · Oct 6, 2014

AFR 335CC PORT Headed 540 BBC engine on the dyno today....
AED1000
Foxwell Air Gap with plenum work and matched to the heads
Heads were Version 1. Foxwell valve job and some chamber work
Crane 1.7
Straub Custom Camshaft Hyd Roller
.665/.643
248/248
107 Sep
Morel 4603 lifters
10.5 to 1 Pistons
Callies Rotating Kit
Gen 6 Block
Stef's Heads up pan with full 2" kickout on PS.
Going in Board members car behind a richmond 6 speed
FINDING A DECENT BBC CAM ON A TIGHT LSA CAN BE A PROBLEM AT TIMES< HERES A FEW
http://www.claysmithcams.com/big-block-chevy-11/
keep in mint tighter 106-108 LSA tend to improve cylinder scavenging efficiency

Cruiser build 6200-6400 peak
BP93/10% will be used.

738HP @ 6100
720#/ft @ 4000
2" headers which is what is on the car.
1" 4 hole spacer worth 10#/ft below 5000 rpm
1" Open spacer worth 10HP above 5000 rpm

HERES AN EARLY DYNO PULL DURING TUNING

theres always a big factor in the selection of engine components ,
for most of us and thats obviously the COST VS potential power gained.
what many guys fail to look at is the valve lift vs flow numbers, and intended application,
I does you darn little good to purchase a killer BBC, set of 360 cfm rectangular port cylinder heads that flow 400- 450 cfm at .800 lift if ,
your cam selected max's out a .650 lift, its not designed to maintain valve control at over 6000 rpm, and your intake port flow stalls at 390 cfm
especially on something like a 9:1 compression 454 BBC, with a typical 750 quadrajet carburetor on a Stock style low rise dual plane intake,
yet I see similar mis-matched components rather frequently , usually from guys that got KILLER DEALS on lightly used race engine parts they picked up at bargain prices at swap meets.
look over the parts your selecting very carefully and use some logic in matching components, if you realistically won,t be running the engine over 6000 rpm, and your displacement is under 427-454 cid, your very unlikely to benefit

lets do some MATH
lets assume you want to build a kick ass 540 BBC

a 540 has a 4.25" stroke and 5200 f.p.m. in piston speed would be a reasonable upper rpm limit (7350 RPM )if you intend to maintain reasonable long term durability.
now that would MANDATE a solid lifter cam (ideally a roller solid lifter) valve train to maintain valve train stability in most cases.
at 7350 rpm a 540 will in theory use 1723 cubic feet of air PER MINUTE
thats 215.4 cubic feet of air per minute per cylinder if divided equally but each cylinder draws
67.5 cubic inches per cylinder x 3675 intake strokes,
thats about 1723 cubic feet of air per port, per minute, and 3675 intake strokes per minute
thats .469 cubic feet per intake stroke ,
(theres 144 cubic inches in a cubic foot) and a cylinder in a 540 has 67.5 cubic inches.
theres 8 cylinders that need 67.5 cubic inches of air volume 3675 times per minute.

but remember an intake port and intake valve ,flows air during about 250 degrees in a 720 degree cycle, thats about 35% -40% of the time,the engines intake valve is effectively open and flowing air, and remember the exhaust scavenging,
has a huge effect on intake flow rates.
lets look at an intake port that flows 400 cfm which you might need to allow a 540 to flow enough air because even if the heads potentially flow 400 cfm the intake manifold or some other component may not fully keep up!
flow rates are measured on a flow bench at constant flow rates,
but theres 61.25 intake strokes per minute, per cylinder.
in theory a port that flows 400 cfm will flow about 160 cfm during the 40% of the time its open in the 720 degree cycle. thats 160 CFM x 144 cubic inches,23040 cubic inches
/61.25 intake strokes per minute= 376 cubic inches
376 cubic inches x 61.25 intake stroke per minute +23039 cubic inches

philly · Dec 6, 2014

wow! alot of money in that combo but it makes for a real killer on pump gas!

AFR335 Headed 540 on the dyno today....

grumpyvette

Administrator

philly

solid fixture here in the forum