FLPACKERBACKER
Member
just wondering if anyone has had a 3x2 intake extrude honed.was it worth the money or am I better of leaving it alone?plan on doing a 4 inch stroke 348.probably 11.5-12.5 cr with aluminum heads.
eric
eric
extrude honing intake
- Thread starter FLPACKERBACKER
- Start date
You will be better served all the way around with the Edelbrock 2X4 intake. The three two intake probably will not support more than 375 maybe 400 hp. The 2G carbs kinda run out of power at 5000/5500 rpm, not enough cfm for serious performance. Great carbs/intake for a street cruiser/bruiser though.
Skip, the Pontiac tripower intake is a lot better piece than the 348 intake. Dave at SD looked at a 348 tripower intake for me some time ago...... he said "don't use that thing"...... and he does lots of Pontiac tripower engines.
Dave
Dave
The Pontiac intakes use bigger outboard carbs. I always wondered if a 348 intake could be modified to take the bigger pony carbs and if so, could the ports and runners be worked enough to take advantage of it.
I wondered the same thing Cecil, there is a bit to be gained by gasket matching and blending the runners in about an inch or so. 1/2" phenolic spacers give a tad more plenum volume. Blocking off the heat passage will help performance. You could try and open up the divider between the ports. You may be able to squeeze a little more out of the three two setup. Still, all in all you would be better served with a good after market single four or dual four setup if your looking for max power. Don't get me wrong, I'm a big fan of the three two setup. You can make a real street screamer with three two's. Throttle response is phenomenal and you get to sip fuel through a two barrel when you don't have the wick turned up! If you insist on a three two manifold I have one that has the heat crossover blocked and the dividers opened up a bit. I will even gasket match it for you and blend the runners.The Pontiac intakes use bigger outboard carbs. I always wondered if a 348 intake could be modified to take the bigger pony carbs and if so, could the ports and runners be worked enough to take advantage of it.
Suggestions for 3x2
Ray:
I plan on using the 3x2 intake on my 1961 348 build. Block is .060" over, crank is 409, rods are BBC, pistons are Ross forged strokers (from Aubrey). Carbs and intake are dead stock 3x2.
What are some things I should consider to get a bit more performance from that induction system?
Thanks in advance!
TomK
Ray:
I plan on using the 3x2 intake on my 1961 348 build. Block is .060" over, crank is 409, rods are BBC, pistons are Ross forged strokers (from Aubrey). Carbs and intake are dead stock 3x2.
What are some things I should consider to get a bit more performance from that induction system?
Thanks in advance!
TomK
FLPACKERBACKER
Member
thanks for the replys.this will be a street car for the most part.I would be up to adapting the holleys if anyone has done that.it is a shame nobody makes an aftermarket aluminum that uses the larger carbs.
eric
eric
I don't think you will have room for bigger carbs...... I tried fitting one small Rochesters and two of the larger Rochesters, Pontiac style..... won't fit without some major work.
Dave
Dave
Aha!
I just re-read your original post, and your last one where you mentioned: "it is a shame nobody makes an aftermarket aluminum that uses the larger carbs."
Then it dawned on me that you were going with the aluminum heads, which means bigger ports and no chance to use stock 3x2 intakes. I missed that. You were asking if someone makes aftermarket 3x2 intakes for the Big Heads, I was thinking "small ports". Hence my previous posts.
If you are not adverse to the suggestion, you might shoot for multiple carbs using the 2x4 approach, those are available aftermarket. Is that what you might be looking for?
Best,
TomK
I just re-read your original post, and your last one where you mentioned: "it is a shame nobody makes an aftermarket aluminum that uses the larger carbs."
Then it dawned on me that you were going with the aluminum heads, which means bigger ports and no chance to use stock 3x2 intakes. I missed that. You were asking if someone makes aftermarket 3x2 intakes for the Big Heads, I was thinking "small ports". Hence my previous posts.
If you are not adverse to the suggestion, you might shoot for multiple carbs using the 2x4 approach, those are available aftermarket. Is that what you might be looking for?
Best,
TomK
Oh yeah!
I forgot about that (probably since it's no where near my price range
).
Good call!
TomK
I forgot about that (probably since it's no where near my price range
).Good call!
TomK
You pretty well have to go with a large port manifold if you use large port heads. The small port manifold would choke the engine. I'm sure extrude honing would help but I don't think it would do enough. I think it's also a fairly expensive process.
I was looking for the post about the Barry Grant Six Shooter manifold but I couldn't find it.
With a little work I think an Edelbrock dual quad could be converted into a tri power setup.
Here's an illustration from a David Vizard article that shows what an ideal intake and manifold port would look like. It's important for the manifold runner to get bigger than the intake port in the head. Here's a link to the artical...
http://www.gofastnews.com/board/technical-articles/1247-porting-school-8-optimal-port-areas.html
I was looking for the post about the Barry Grant Six Shooter manifold but I couldn't find it.
With a little work I think an Edelbrock dual quad could be converted into a tri power setup.
Here's an illustration from a David Vizard article that shows what an ideal intake and manifold port would look like. It's important for the manifold runner to get bigger than the intake port in the head. Here's a link to the artical...
http://www.gofastnews.com/board/technical-articles/1247-porting-school-8-optimal-port-areas.html
Jim...I just came across this...........
http://www.hubgarage.com/mygarage/TechAtBG/blogs/6737
HOME Page below.
http://www.barrygrant.com/
Ron
http://www.hubgarage.com/mygarage/TechAtBG/blogs/6737
HOME Page below.
http://www.barrygrant.com/
Ron
FLPACKERBACKER
Member
thanks again for all the info guys.was really wanting the 3x2 set up just for the cool factor and i already have the intake and carbs,.but a 2x4 will also work and will look just as good with my set up
eric
eric
Aducati4me
Well Known Member
Fathead racing, do you have any pics of how you opened up the dividers in your tri-power manifold? Or a good explanation of how you did it? I'm not experienced in this area at all so please bare with me.
Wow, people read these old posts? I'm going to be in the shop today. I'll dig that intake up, if I still have it! I may have sold it, can't remember. Basically there is a divider under each carb mount. You would start by grinding a slot right down the middle. Do it a little at a time, don't gut it. The goal is to use both carb barrels instead of just one. You would want a 1/2" phenolic spacer on all three carbs also. Actually by using the spacer you are doing kinda the same thing. You definitely want to block off the heat passage.
Aducati4me
Well Known Member
Fathead Racing. Thanks for the reply, yes these old posts are full of great information from experienced people. I'm actually using a 2" spacer under each carb. They are 2 barrels instead of an open plenum. I can cut out the divider and open them up to one big oval hole if you think that might help or accomplish the same goal. Just a thought