wow that was around 35 hours total porting I'm glad that's over . fingers crossed it doesn't crack once it gets hot .the previous photos were after 10 hours that's when i thought i finished the 1st head . i spent around 4-5 hours today deshrouding the combustion chamber . i can now see why that is so important , i almost wasn't going to do that . well i'll let yous all know how it goes no doubt .

 

Looking good bro

 

Excuse my ignorance but what is "deshrouding"

 

if you look at the photo above , you can see the carbon ring / or old gasket pattern on the heads . if you look closely there's two rings next to each other .grind / port the thick black carbon mark back to the outer skinny ring , i'll put new photos on here after work . imagine as the valve opens or closes the air tries to rush in but the valves are so close to the chamber edge it don't flow in that well . after grinding about .120" off each side then open a valve man the difference . that alone would help heaps .

 

So then deshrouding is removing the material around the valve guide (to within reason of course)?

 

depends mate .
i have heard people call bowl blending ''deshrouding'' . what I'm calling de shrouding is grinding the side walls of the combustion chamber closest the inside of the head gasket (FLAT HEAD SURFACE) . it would increase chamber size in cc , but flow heaps more if the rest of the port is working with it . besides i will be gaining compression from 496 cubes + milling heads & block to suit .

 

OK i see now you were looking in the middle of the "bowl" at the guide . sorry not there , all the way out near the gasket line . the deshrouding hasn't been done in this photo .
it took me a month to post the pics haha . & i only finished deshrouding them yesterday you will see when i put my next lot of photos , i'll make note at bottom of photo .

 

I got ya now, I've heard that called CCing but hey, deshrouding works for me too Look forward to the pictures......

 

k

 

hope it works .

 

yippy ki aye . these are finished now as far as porting goes . i took the heads back down the machine shop today . well the photos aren't the best but as you can see there's heaps more volume , with 492 cid they should work well fingers crossed .

 

Nice job in the runners buddy. I can tell it's not your first set that you p&p.

 

it feels great to have dropped them off at the shop . its make or brake time . on my own stuff i find it hard to finish 30 hours is a long time to be starring down runners & trying to keep em all the same abit nerve racking .
BTW there's no polish or tape or nothing that's burr finish .

 

Burr finish is basically what ya want on the intakes anyway, looking good man.

 

Looing good, maybe one day I'll get up the guts to do a set of heads...

 

have a go on a crappy set of heads first . i bought my makita electric die grinder for 129 Aussie $ & 3 burrs 1/4 inch shank , flame , oval , cylinder with round nose it also had a 6 inch shaft that i shortened by 2 in , all 2nd cut . steady as you go . well i think that would cost at leased $1000 au in porting if not more . I'm still not sure what i can & can't do with the seats as I've really only ported 2 strokes . next I'd like to attack a 6 cyl hemi head , my mate spent $1800 au on porting his cast 6 head , & he still has the templates . the engine builder is expecting 350 - 400 hp out of a 4.3 liter aspirated six that should put a centura ( french simcar) into the low 13-high 12's , perfect for picking fights with chevs & fords . oh yeah my mates is running 125 of gas as well in his . got 2 head off to work cyas .

 

your friends car would be a killer

 

yeah it could go faster i'll get some photos of it today . i had a thought yesterday about using my brothers centura as a all out drag car & using my b motor in it with 200 - 300 shot of nos & put a 318 back into my Ute as a street car / tow car . my two Chevy brother mates are fighting over the idea . one of the brothers coming round & he's thinking about getting a kb hemi block for his tube chassis car . haha if ya want to go real fast ya need the dizzy out the front . hell even fords dizzy's are out front .

 

my mates 1974 chrysler centura 265 hemi 6 cylinder 4.3 liter drag car will have 125 shot of nos as well .

 

Just got the Mopar Muscle mag. there givin away a 490 stroked 383, this is a good thing for us. they dyno'd it and came up with 12in of vac, 537hp at 5300rpm, and 628 ftlb at 3900 rpm. I want to build the 383stroke meself. this was assemblrd by Muscle Motors, bout an hour down the road from me, think this is the way im going, and the way you are going. hope you get a tip or two from the article.

 

i'll see if its at the news agent yet , if not i'll look on line . what heads & cam . that's good power for those rpms , it would last a long time as well .

 

From the article, its a seasoned 68 block, set for a 4.25 stroke, bore,4.28, with 9.3:1 dimond pistons. Roller cmshaft. They used 906 heads for this. Thought this was up yer alley, as well as mine.

 

i couldn't find it oh well i'll see it no doubt that's great there using 906s are they ported ?

 

http://www.moparmusclemagazine.com/m...018/index.html Here ya go buddy. Should cover it

 

wasn't there a 3.7 liter hemi slant six made?

 

yeah the slant we stopped using them in 1970 , then went 215 , 245 & 265 hemi six a whole new ball game . its like a 273 to a 340 . there is a chic that runs a 225 slant in a abody over here & they super charged it . it used to go 14.00 all day aspirated & 13.6 charged up .

 

i seen the video thanks .
by the looks of things i think i done all right . there's is a bit more , i should be fine with wall & water jacket thickness .