dart 215 pro 1 platinum upgrade on 383 sbc

[steve cowan]

i am looking at finding a bit more power in my 10.5 :1 comp pump gas 383sbc

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this is my ride,it is a 1972 hq holden ute with hj front end bumpers etc,i have had the car for 10 years and completely rebuilt car except body and paint,the car has run a best of 11.10 @ 121.5 mph with a 1.53sec 60ft drive to the track and home again three and half hrs round trip at 60 mph highway driving,i race and test at least once or twice per month but not in summer.
i have not had engine on dyno but i think it makes 500 or so,
i want to rework the cylinder heads myself but i am a true novice at head porting,i have read a bit of theory but never put anything into practice,i have a bit of equipment and willing to have a try at improving the whole engine package,i assemble and blueprint my own engines but i do not work in the industry as i am a highrise construction worker who puts in 60 plus hrs a week and like all you guys here are a bit time poor.
i picked up my cylinder heads today from the machine shop as they did a freshen up on the valves and seats,3 angle intake and standard 45-46deg exhaust,guides are still good as i have done 12-18 months on this engine and a fair amount of street driving.

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i want to share what have done today as far as inspection of valves and seats,i checked and cc the combustion chamber,an intake and exhaust,took some basic measurements,there a a heap of photos i took today and i am looking for a direction to start as far as improving the cylinder heads,i have three cams to choose from and i have previously stated elsewhere the car ran the consistant 11.1s with the 112lsa nitrous comp cam as at the time thats all i had in small base circle,any help appriciated,i will put up as much imformation as possible,answer any questions to the best of my ability,happy to take constructive feedback

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valve throat at 85%,1.6'' valve 1.36''throat,window of exhaust 1.5'' x 1.42'' = 2.14'' at the apex of ssr

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intake port 1.25'' x 2.21'' = 2.76''
MCSA at the pinch 1.03'' x 2.03'' = 2.09'' intake window at SSR apex 1.85'' x 1.63'' = 3.02''

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3 angle on the intake and standard 45 - 46 deg on the exhaust

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[Carnut1]

Get them flowed. You know how they run stock. After some porting get the flowed again and then track time to compare times and speed.

[steve cowan]

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230 seat and 600 on the nose, i am using xledyne super 7 ti retainers and locks

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i blued the seats and inspected seat width on valve face,i did not measure but looks like it carries down to the margin area of the valve face???

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this is my own flow bench,apparently capable of 400cfm at 28 inches from a standard 10 amp power outlet,i am still in learning phase with the bench and performance trends software,

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i made this small porting station last year and even though it is small it is good as far as keeping mess to a minimum,i have a air die grinder and an electric,head stands,different burrs and sanding rolls and flappers and stones for finishing

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i bought the cnc super victor intake and have been using on this engine,surprising enough the fitment was good so i have not touched it

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with the manifold i done the same as the cylinder heads,just a clean uip with a 60 grit roll,it has never shown any reversion problems but maybe because of the cam with a 112 LSA ?????

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[steve cowan]

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i did not know how to measure the SSR so i ran a length of solder from the rule is the deck face at the intake,and at the front is 0.230'' at the port entry to deck,so at the apex it measured 1.06'' probably not the best way to measure but thats all i could come up with at the time

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[steve cowan]

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this is the cam i was using previously as i had no other cams with small base circle to clear the scat i-beam conrods

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a friend of mine gave me cam,it ran a 10.1 @ 131 mph at 3100pounds with a 9 inch slick 383 sbc on avgas,i can use this cam with my scat H-beam rods which are getting crack tested and resized and a arp 2000 rod bolt upgrade at the moment

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i have this cam as well that i have not used,it is a small base circle if i choose to keep using the scat I-beam rods,any cam feedback appreciated,i am thinking comp roller with std base circle and H-beam rods any thoughts ?????

[Newold1]

From the care and detail of your work shown here in your post I think you are already "light years" ahead of a lot of the "noise" you may receive on the internet including some here on Speedtalk. So just focus on the maximization of those cylinder heads and intake manifold from measured flow improvement and then insert some expert (professional) camshaft design information to get the head/cam combination working great together. Obviously beyond that all the other things that can be maximized like car weight, gearing, drive train, suspension, tires, traction and driver skills to achieve the best possible time slip your car can generate. No magic, just small careful steps punctuated by testing will get you there. Nice work Keep it up! Cheers!

[Carnut1]

Do you have calibration plates? Do you have Pitot probes? ST search engine has issues now but somewhere I have three threads on the Dart 215's I am working up with lots of pics.

[B Original]

What carnut is suggesting with the pitot tubes is what you need to know where the air is flowing in the ports. The shows the dead areas and the fast to super fast areas; and yes you can move air too fast through parts of your intake ports causing turbulence so look to identifying turbulence in the port. You will never get a perfect even flowing port but you can work to eliminate the fast turbulant and slow flowing areas so you can work toward a higher flowing average gradient. A smoke trace can be used but not as accurate in identifying these area's but still a good tool.

And don't discount the seat work the most important work you can do is in the seat. Tho old school 3 angle valve job is archaic a good seat profile cutter is golden below .250-.275 of valve lift as half of your lift duration is spent below this lift. Some on here will discount this opinion but don't listen to the nay-sayers.

Chamber work is important too, with this cylinder head a .025 flow ball will show you where to relieve the chamber on the cylinder wall side of the intake valve. although you may think you are increasing the chamber area by relieving the transition from the center of the chamber to the valve seat making for a smooth transition is a great unexpected place for improvement in the intake and exhaust too. The idea is to make it look like the sand on the beach as it transitions into the ocean, like a long smooth contoured roll toward the valve seat.

Port finish don't make it too smooth, take a lesson from some of Carnuts work pictured in his dart pro post's. He has terrific finishing techniques if you are apprehensive to do artwork with a bur Like Carnut, do your final finish surface on the intake port with a 40 grit roll. Contrary to popular believe of following the name of port and POLISH disregard the POLISH part. The rough surface creates a thin layer of turbulance called a boundary layer that acts like Teflon resisting pooling of fuel that falls out of suspension and keeps it suspended in the air stream.

Like Carnut suggested get some Pitot probes and also get a set of flow-balls. I don't put as much importance into the calibration plates ( Unless you are racing someone elsess flow bench lol) if you always port on the same machine you are looking to improve from the flow numbers you just took previously, you are improving on your previous reference #'s.

[Carnut1]

Thanks for the kind words, I would like him to start off with a calibrated bench because he should have no problem adding 30 cfm to the intake ports. If his bench is accurate and what he has flows 270 cfm now and a straight forward porting brings him to 300 cfm I would be happy with that. The ssr solder looks dead stock, pinch and bowls basically untouched. He has a good start with his equipment and I will help if I can. Thanks, Charlie

[Warp Speed]

Yep, without calibration plates or a pitot he'll never get that thing to run! Lol

[GARY C]

What did the runner actually CC?
As a novice head porter I would stick to the basics of thinning the guide, slightly widen and massage the short turn as well as the push rod pinch. I feel the head is border lined on being to big for what your doing but I could be wrong.

If you can get a trim to fit intake gasket I would go that route as I would not want to bell mouth the entry to fit a shelf gasket only to have the port shrink to a small PRP, I would want to reduce cross section size change as much as possible, you can pick up good cfm with only a 5 to 7 cc change to the runner but you can also hurt the head by going crazy on it if you have no data to show power gains from porting.

[user-9274568]

Yep, without calibration plates or a pitot he'll never get that thing to run! Lol

Finally you get it!

[Carnut1]

Yep, without calibration plates or a pitot he'll never get that thing to run! Lol

Finally you get it!

Funny, but I doubt it.

[treyrags]

Like Gary curious what the runner actually is in volume. Did you find the length of the center of the port and figure the average CSA? Do you not a factor in the radii of the port in measuring your CSA?

[Warp Speed]

Yep, without calibration plates or a pitot he'll never get that thing to run! Lol

Finally you get it!

Funny, but I doubt it.

Are you guys really serious?!? LOL
I mean, tools and information are good, but PLENTY of great cylinder heads have been developed without the use of either.
I know you guys are strong proponents of such, but really?

BTW Carnut, you need to actually get something to run with success before you start throwing jabs, because all the stuff you have posted over the last year or two is all theory, and has yet to run on anything!
And while I'm at it, I don't think your floor is near wide enough to require that monster vane/fin, but that's just my opinion. It obviously doesn't count here in the midst of all these experts, but hey, it's a free country!