523 dove headed stump puller *** update***

i hit the dyno yesterday and was pretty imressed with my latest build. the motor ran pretty good for a couple pulls before having lifter pump up problems.


combo:

523cu. in.
4.4 bore
4.3 stroke
big valve dove c heads that flow around 330cfm at .600 lift (20 year old porting job)
weiand stealth intake
old 750 holley DP
2" open headers
hs roller rockers
8.8:1 comp ratio
34 dergrees of timing
87 octane

cam: comp shelf grind. 270h extreme 4x4
int. exh.
.554 and .574 lift
dur. at .050" 226 234
lobe sep. 111.0




the best pulls before the lifter trouble netted me with 615 lb ft torque at 3200 and 510 hp at 5500.

we never did find the torque peak because we had not pulled it low enough in the rpm range. the every pull the torque peaked at start.
i am sure by the look of the numbers, there would have been a bunch more torque down low if we had run it down to 2000 for a start.



what do you guys think?

i am curious if a different cam would pick this thing up even more down low.


barry

What are you doing with it? Looks like a torque monster! A custom cam may suit you good.

it is going in a 5000 lb street cruiser trail toy truck. '74 f100 4x4

Should have no problem moving that truck!!! Awesome pump gas build!

i was suprised by how little timing up top this thing wanted. peak power was at 34* and 36* dropped 9 hp at peak.

it also seemed to like being a little lean. i the area of low 13 afr's
bsfc came in around .42 - .45 in the meat of the pull.

i think this thing should make for a pretty good street motor.

thought about a tighter LSA?

Tennessee Bullitt wrote:thought about a tighter LSA?

honestly no. but only because i dont know enough about the effect of lsa to spec anything diff.
what change would i see if i tightened it up?

i did some reading on lsa. now have a little unerstanding of it.

nice numbers gives me a lil more hope for the iron 512 im buildin

well turns out not only were the lifters pumping up, but i had a exhaust lobe going flat.

That combo or something simular sounds like what im looking for good low end tourqe to get my 5000lb car moving .

fastbarry wrote:well turns out not only were the lifters pumping up, but i had a exhaust lobe going flat.

pumping up/ thats what you want is for them to be pumped up at rpm, rockers set wrong?

fastbarry wrote:well turns out not only were the lifters pumping up, but i had a exhaust lobe going flat.

pumping up/ thats what you want is for them to be pumped up at rpm, rockers set wrong?

i just tore back into this thing due to some head gasket leakage.

i found sone pretty good scuffing in cyl number one. i am trying to figure out the cause.

i think we can get away with some honing and re-ring.


i had a thought, while it is apart, would there be any advantage to swapping on a pair of ported iron cj castings that i have on the shelf?

There may be some advantage if you were going to use it higher up in rpm ranges, but port velocity is not going to be good down low. I would stick with the DOVE's if it were mine. I did a 552 several years ago, that made about 600hp on 110octane race fuel, with 18" of vac@1000rpm. It had DOVE heads too, and pulled off the line in mud drags like a freight train.