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alright so i just joined the forum and i have a 67 firebird convertible, come springtime i want to start a build i have a 400 motor out of a late 60s pontiac its got a gto intake with a carter carb not sure of the cfm basically id like some suggestions on what to do to get a lot of power out of the car, ill be buying parts over the winter and have more cash in the springtime to buy other parts. Really i have no idea where to start with the build im only firmilar with simple stuff like exhaust and putting a bigger carb on it so i was hoping some of you guys would give me a hand with what bore stroke heads etc i should use to get the most power, thanks.
 

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First get the casting date from the back of the block on the pass side of the dist.Then get the engine code from the front pass side of the block under the head deck.Then get the head casting numbers from the center exhaust port on the heads.That will be a good start.The intakes were all the same depending on engine code.A 350 could have the same intake as a 400.Thenyou need to decide what your wish list is.A race only engine,a race street engine,pump gas hipo street engine.Auto or stick shift etc etc etc.Tom
 

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Yes, make a positive ID on exactly what you have. THEN, you can start making decisions of which way to go with your engine build. Along with the ID numbers mentioned, also check the casting number of your block. It's located on a pad, just below the rear of the passenger side head.

And, as said, you must decide on how much power you want, A mild, but fairly spunky low compression, very pump gas friendly street engine, will take a completely different recipe, than a high torque, high powered stroker.

IF your 400 does indeed have a late '60's block, and it is rebuildable, it will make a good foundation for either a mild 400 rebuild, or a stroker.

If it has high compression, low performance 2-barrel heads with press-in studs, then there are probably better heads to use for your build. Then another thing to decide is whether to use engine parts that are numbers matching, or close to it, or forget the numbers and build for your purposes.

For example: '67 was the 1st year of the 400, and the 4-barrel they used was a Q-jet. But, these were all 750cfm. There are later model Q-jets which are 800cfm and have some desirable features, which the early Q-jets did not have. But, they look a little different, have different style throttle levers, chokes, etc. So, they won't look original, to those who are familiar with Pontiacs. But, the function can be better, with a properly built unit. :smile22:
 

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