Ahhhh...

I was explaining to Cory today that I just realized I didn't look to see if his intake manifolds were match ported. I trimmed out the intake gasket to fit the big head ports but I didn't turn the carbs upside down to look at the manifolds. I'll bet they're stock size..... so there is another source to unlock potential power. I told Cory he could order match ported manifolds from CB or just get big beef manifolds and we can do the work ourselves. It would be interesting to get horsepower readings for the way it's set up now, then after changing the exhaust, then again after match porting the intake manifolds, just to see what we are gaining.

Spending Cory's money is starting to be really fun.

PaulEllis posted:

I was explaining to Cory today that I just realized I didn't look to see if his intake manifolds were match ported. I trimmed out the intake gasket to fit the big head ports but I didn't turn the carbs upside down to look at the manifolds. I'll bet they're stock size..... so there is another source to unlock potential power. I told Cory he could order match ported manifolds from CB or just get big beef manifolds and we can do the work ourselves. It would be interesting to get horsepower readings for the way it's set up now, then after changing the exhaust, then again after match porting the intake manifolds, just to see what we are gaining.

Spending Cory's money is starting to be really fun.

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PaulEllis posted:

I was explaining to Cory today that I just realized I didn't look to see if his intake manifolds were match ported. I trimmed out the intake gasket to fit the big head ports but I didn't turn the carbs upside down to look at the manifolds. I'll bet they're stock size..... so there is another source to unlock potential power. I told Cory he could order match ported manifolds from CB or just get big beef manifolds and we can do the work ourselves. It would be interesting to get horsepower readings for the way it's set up now, then after changing the exhaust, then again after match porting the intake manifolds, just to see what we are gaining.

Spending Cory's money is starting to be really fun.

If you go the big beef manifolds route- make sure there is room for them, as they are a fair bit taller (6" vs 4") than most IDF/Dellorto manifolds. In my car (older pan based IM) I've mocked it up and think I will have enough room for IDF's, GB 580 manifolds and air cleaners. IDA's and Berg's short (GB 587) manifolds barely fit, with the rear velocity stack on the right side coming really close to touching the car body. There's no way to get air cleaners in there with IDA's....

Dyno readings before and after upgrading the exhaust and manifolds would definitely interesting to see; please post the results if you guys actually do it. Al

There seems to be lots of room in our Becks, but I'll need to look again to be sure. As far as Dyno tests, it boils down to time and money.

PaulEllis posted:

 As far as Dyno tests, it boils down to time and money.

And that's why I said "if you guys actually do it."

There is also the issue of how well the manifold head flange shape matches the available mating area on the heads.  Some of the larger-port configurations don't match the head flanges without some machining of either the manifold flange (which starts out too big in some cases) and/or the surrounding tinwork.  The type 4 heads are so much nicer to mate a manifold to, but the type 1 is what it is.  I don't have the Big Beef manifolds, but there was sufficient wall thickness to machine-mate the outlet hole size/shape to my 044 heads.  Fun project, but prior port-matching experience (or an advisor who's really good at machining/polishing the runners to offer suggestions) is important.

Just a note, guys- don't bother polishing the insides of intake manifolds; you get better flow and you don't get nearly as much separation of the air/fuel mixture if the ports are left somewhat rough. Fuel can drop out of suspension on polished intake manifold walls, creating lean conditions in the combustion chambers. 

My buddy Steve said he has been machining the bottom of the manifolds so they lean in more and give more room to reach the adjustment screws etc.

ALB posted:

PaulEllis posted:

I was explaining to Cory today that I just realized I didn't look to see if his intake manifolds were match ported. I trimmed out the intake gasket to fit the big head ports but I didn't turn the carbs upside down to look at the manifolds. I'll bet they're stock size..... so there is another source to unlock potential power. I told Cory he could order match ported manifolds from CB or just get big beef manifolds and we can do the work ourselves. It would be interesting to get horsepower readings for the way it's set up now, then after changing the exhaust, then again after match porting the intake manifolds, just to see what we are gaining.

Spending Cory's money is starting to be really fun.

If you go the big beef manifolds route- make sure there is room for them, as they are a fair bit taller (6" vs 4") than most IDF/Dellorto manifolds. In my car (older pan based IM) I've mocked it up and think I will have enough room for IDF's, GB 580 manifolds and air cleaners. IDA's and Berg's short (GB 587) manifolds barely fit, with the rear velocity stack on the right side coming really close to touching the car body. There's no way to get air cleaners in there with IDA's....

Dyno readings before and after upgrading the exhaust and manifolds would definitely interesting to see; please post the results if you guys actually do it. Al

Can you mil down the tops and bottoms of the manifolds? Maybe an 1/8" each?

Sure!

Just make sure they are flat and true when done.

If all you need is a little bit then yes, they can be skimmed at both ends for clearance. The Berg manifolds are all pretty hefty around the fastening points so there's material to remove. I've seen older CB Perf. manifolds that have broken at the head end (they were pretty thin around the fastener area) so any more than a skim to be sure the flange is flat would be pushing it.