New SBC Cylinder Head Project

[68Chevele]

Picked up a set of Dart Platinum 200cc heads with 49 cc chambers for $385 complete this week. Took them apart and and these do not need much work to be great heads and move some air. Looks like they have been bowl ported and need a new home with my newly ported Victor Jr. A quick cleanup and valve job should make for some exciting performance next year.

 

[68Chevele]

Heads are apart, ready for some cleaning and mild port work with a new valve job. I am wondering if the 39° valve seat that David Vizzard used on a head with smaller valves would work on there. Only one way to find out.

 

[77cruiser]

Some of those Speed talkers sure like 50 deg.

 

[68Chevele]

Some of those Speed talkers sure like 50 deg.

I know the NHRA guys sware by the 50° seats but David seem to think that a head with a smaller intake valve can be fooled with the 39 seat angle and he had the flow bench data tp prove it.

 

[68Chevele]

Had some BBC 781's flowed a few weeks ago and my porting with valve job were better than my buddies 990 sq. ports had tested last weekend. He is not happy at all.

 

[Leadhead]

Great job man! What engine are those going on?

 

[cage2592]

Yes ! We need Engine and Car data ! Can you please also include before and after pictures of the port and polishing? Will you get these reflowed? I would love to see these on a 400+ CI SB. I have a 9.4cr 406 in the shop I've been considering a 200 to 220 head for and a turbo. Never had a turbo car and I'm wanting to see how it fares.

 

[68Chevele]

Great job man! What engine are those going on?

Actually nothing right now, the 781's have been on the shelf for over 10 years. Dang peanut port heads work too good, lol. I have another 468 though that I have to pull the gen VI head off as I did not know you have to drill the block so I will waste a pair of head gaskets. I am thinking of putting them on that engine.

 

[68Chevele]

Yes ! We need Engine and Car data ! Can you please also include before and after pictures of the port and polishing? Will you get these reflowed? I would love to see these on a 400+ CI SB. I have a 9.4cr 406 in the shop I've been considering a 200 to 220 head for and a turbo. Never had a turbo car and I'm wanting to see how it fares.

I have two plans that the Dart 200's might be on. One is a cheapo 355 that looks like a junky street engine, the other is to put these on over my Sportsman II 200cc head on the current 358 and switching to my ported Victor Jr.

 

[68Chevele]

It has begun, the valve job on the 200cc Darts is going well. I am putting on the intake side a 37-45-60-70 degree valve job with a 30 degree back cut on the valves, on the exhaust side it will be a 30-45-60 degree with no back cut as that causes reversion. Pictures coming soon.

 

[cage2592]

 

[Nashville Cat]

68Chevelle,
I have a set of the E-street Edelbrock heads for BBC. Planning on pocket-porting the radius under the valves, smoothing the valve guides, etc.
I might do some contouring inside the port if I can follow what Vortecpro is talking about.
Or just bring them to you ? LOL Not kidding, if you have the time or even do this ?

 

[68Chevele]

68Chevelle,
I have a set of the E-street Edelbrock heads for BBC. Planning on pocket-porting the radius under the valves, smoothing the valve guides, etc.
I might do some contouring inside the port if I can follow what Vortecpro is talking about.
Or just bring them to you ? LOL Not kidding, if you have the time or even do this ?

Let me know when you want to stop over, Might be a long walk to Minnesota though, lol. I just looked at the specs on those heads, they flow about the same as my 781's I did. A good cleanup and get a killer valve job will make them shine.

 

[68Chevele]

Did my checking yesterday with the 49cc heads I have with the flat tappet cam I want to use, .087 intake and .125 exhaust piston to valve clearance so it's good to go.

 

[Nashville Cat]

Let me know when you want to stop over, Might be a long walk to Minnesota though, lol. I just looked at the specs on those heads, they flow about the same as my 781's I did. A good cleanup and get a killer valve job will make them shine.

LOL, I think I'll just do some bowl work and streamline the guides. I can do that in the time it takes to drive to Minnesota (1000 miles?).
I just need to find a shop nearby to do that valve job. Not sure what Scott Foxwell would want ?

 

[Nashville Cat]

Did my checking yesterday with the 49cc heads I have with the flat tappet cam I want to use, .087 intake and .125 exhaust piston to valve clearance so it's good to go.

Did you see the Engine Masters episode trying different single plane intakes on a SBC 406 with old AFR heads ? Making over 560 hp !

 

[68Chevele]

Did you see the Engine Masters episode trying different single plane intakes on a SBC 406 with old AFR heads ? Making over 560 hp !

I did, it was pretty good. I like the header episode better when the beat the crap out of the tubes and only lost 5hp, lol.

 

[68Chevele]

Well this project took a weird turn. Seems the ports on these heads that are 200cc's use a 1206 intake gasket but the intakes I wanted to use may not seal that are 1205 gaskets so I might just put these heads with the 300-25 Holley intake on my 406 now and test with them on the 358. I have to find a way to make the engine look kind of junk though. Wonder what kind of performance difference there will be with these over my 64cc Sportsman II heads. Should be a fun test.