Out with the 340 & in with the 410 stroker!

Ok update.

The 410 short block is back together, this time I used the narrower full groove main bearings, though the main bearings were perfect..I just said what the hay and bought new ones to rid any fault on the lathe job of the previous mains.

See I found some interesting stuff when I was cleaning/checking the block, the crank 'where it radiuses up from the journal and then drops off to the counter weight' was actually contacting the upper part of the main saddle/web and even clearenced itself....

Crank end play was fine and all seemed good except maybe the crank is a screw up by the machinist who finished it...weird, however the crank, where I can assume it contacted, has no wear or damage there...but I have no other explanation for the wear on the upper saddle...and there is no wear/contact marks on the cap at all....

So after checking and checking...................................and checking, I assembled it and checked again, it's good...and if it go's to bits...it go's to bits....I mean I have already rev'd that bottom end 6500+ numerous times and it lived even with the 'assumed contact'

I should have taken a pic but oh well....


Next matter, I bought a flow performance bench kit and built a flow bench, good news...it works.... it mimicked the previous testing with a shown gain from the back cutting and touch up work I had done during the 2 valve job episodes, minor wall polishing n such..
The new numbers I have from the best flowing of the passenger side head [they are now bank specific due to the chamber correcting I did to match the corresponding cylinders to alleviate hot spots and rid as much shrouding as possible] are as follows.....
.100 76.7
.200 147
.300 204
.400 252
.500 284
.530 290.3
they fall off after .530 lift to 269@ .550 and then to 250/248 from .600 on..
I have tested a retested to make sure I am not fooling myself....
To put that into perspective, Heres the down side...
I have 1 intake port 'opposite end of pass side head' that does not want to flow above .490 lift, it don't drop off horribly but it go's turbulent and sits at 250-252 cfm beyond .490/.500 lift.....they all 'look' identical ...but this is agood example of how looks are deceiving....unless you flow every port to make sure...there is a good chance all of us ported head users could have a lazy port or 2

Here are numbers for the no.8 cyl int port mentioned above
.100 66
.200 136.5
.300 197
.400 247
.480/.490 268.4
.500 & on 262/266 and anything above is full blown turbulence....

The other cylinders 4/6 both flow into .530 lift zone at no.4-277 no. 6-274cfm @.530

The good news part duce is that once the intake go's on....the turbulence go's away and I get an average 255-260 cfm flow when I bolt on a victor 340 manifold, I have not tested with the LD340 yet..

On the exhaust 'after guides were cut flat to the roof ' I have as follows.....
.100 to high a pressure to get a reading=40'', bench can't handle that 'yet'
.200 100
.300 141
.400 168
.500 184
.550 190
.600 202
All the exhaust ports flowed within 3-5 cfm through out the entire range w/pipe....the pipe was 2 1/2'' though, it's all I had at the time, the number could be better with a 1 3/4''

So thats where I am at this minute, trying to bring the lazy port up to par, once I am satisfied, or give up and settle... lol, I will move on to the other 2 intake ports and see if I can squeeze 6-10 cfm out of them in the .500 range.

One thing thats funny, and I wonder if anyone else had this thought, ...is that people worry about int/exh flow ratio, not that they shouldn't...but they take raw numbers most of the time [flowed without intake bolted on] and draw the ratio from that to deem good or bad, but the intake dumps the int numbers into the toilet in the end....so hows that ratio again?? LOL!

in other words...if someone wants to bash my numbers based on a ideal int/ex flow ratio....they should relook at the ratio with 255-260cfm in mind and not the clay radius peak numbers, so the above exh #'s against the 255/260, thats not bad at all.

I have also done some 318 heads for fun, with a 1.78 int valve and 10-15 ,minutes of porting I get [email protected] 182@ .400, 195cfm @.500, 200cfm @ .550
The 318 exhaust flows 88 @.200, 120 @.300, 136 @.400, 146 @.500 ended at that lift cause I was using a spring mic at the time.

Hope you enjoy the info.