Doc's dual plane mod and port matching

Published on 04-26-2011 08:40 PM

8 Comments

First, you gotta get your hands on a good intake manifold,,, this one is like me,,, old and weathered...http://www.v8buick.com/images/smilies/biglaugh.gif

Attachment 2362

and on this one I am going to portmatch it to the heads and grind off all the knuckle skinning casting flash on the outside.... you start by placing an old intake manifold gasket on the manifold with the ridges facing up toward the manifold,,, because the gasket is directional and has to be in the right location. http://www.v8buick.com/images/smilies/znaika.gif

Attachment 2369

I anchor the gasket in place with bolts in each end and then mark the inside edges with a marker...

Attachment 2370

This is how it looks when the gasket is removed....

Attachment 2371

then with a die grinder or drill motor and a carbide burr or stones proceed to grind over to the line in the runners...

*****

Attachment 2365

Now on to the Doc dual plane mod,,,first I put the manifold in the sand blasting box and cleaned it up,,,then I take a straight edge and mark the cuts with a marker...
and then I make the first basic cuts with a die grinder and a 1/4'' abraisive cut off wheel... when you get down as deep into the manifold as possible, then switch over to a sawsall and a short blade with 14 teeth per inch because the coarser teeth cut faster in cast iron... and as you are cutting , lube the blade with tap majic or atf to keep it cool and speed cutting...http://www.v8buick.com/images/smilies/znaika.gif

Attachment 2374

after the partitions are removed then go to a 6 in. carbide burr to smooth up the sides, down into the manifold,,, this takes the most time,,, lube the burr with atf often to keep it cool and speed cutting,,, I cut my pressure back to about 40 psi... and put a fan on my compressor to keep it cool....

after the sides are smoothed up, completely clean the manifold inside and out to get all the crud out of it and then paint it....
Behold, the Doc dual plane.....

Attachment 2367

submitted by DocModisett

Categories:
V-8 Nailhead

8 Comments

DocModisett - 04-28-2011, 08:28 AM
- Reply
Looks good , Bob.... one of the guys on the other board did this on a car that he took to the strip and the ddp mod alone was worth .2 sec. in the qtr.... I know , on my personal cars the increase in power was substantial and the gas mileage was not affected at all....

lentzjj - 06-17-2011, 10:56 AM
- Reply
whats up with the pics not working?

Bob - 06-17-2011, 08:03 PM
- Reply
Were you logged in when you looked at it?

If so, what was the error?

lentzjj - 06-20-2011, 11:14 AM
- Reply
oops thought i was but i wasent

goat - 08-21-2011, 08:40 AM
- Reply
Hey Doc, would that work on a 2x4 manifold?

DocModisett - 10-02-2011, 02:53 PM
- Reply
Bob,,, I am quite sure that it would work on a 2x4 manifold,,, the only manifold that I have seen any complication at all on was the factory alluminum single 4 manifold for the 300 ''optional'' engine,,,, and what causes the problem is when the water jacket swings in toward the center of the carb on the sides, you can get into the water jacket real easy in that area.... one fella did and then had to repair the grind thru.....

buickrodder - 01-15-2012, 10:09 PM
- Reply
Very interesting, .2 is like 20 HP, well worth it. The 64 300 aluminum intake may have a problem but the 65 300 intake is iron and exhaust heated so it should be ok to modify.. Should also work on the 364. I have owned factory experimental 2x4 364 and 401/425 intakes the latter was modified in this same way just like the factory 409 Chevy intakes.

63rivguy401 - 09-27-2012, 11:26 AM
- Reply
Doing the same thing to my intake for my 63 Riviera 401.

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