help, what should I us to build motor

[cars-r-us]

I have owned a lot of Pontiacs, I restore them for me, and all have been numbers matching, or all pure stock on outside and inside. Well I bought two firebirds, one is a 71 Esprit, the other a 72 Formula. anyway I want to build the fastest motor I can, useing the parts I have on hand, they are all Cast Iorn parts. I'm not close to being a gear head or build fast cars. So I need help.
Here is what I have, what would be best parts to use?
Motors
1971 400 YS
1972 350 YU
1972 400 YS
and I know a man that has a 1973 455 for sale, but don't know the code for it.
Transmissions
350
400
4 speed muncie
Heads 4X
6X
7K3
Intakes I have (5) 4 bbl and (6) 2 bbl

What cam would be best useing one of the motors I have?

I know this motor will not be the fastest with these parts, but I don't plan to put 5000 in a motor. It will not be a race car,Just looking to get the most horse power out of what I have. I know someone out there knows the best combination for what I have. Thanks so much.

 

[1980Esprit]

I think we would need casting numbers from the motor blocks. You could build them all to go fast but requires money to do with any of them. (Old saying- no replacement for displacement) I would personally choose the 400 because it has 3 inch mains compared to 455 with 3.25 mains. Theoretically You could in turn rev a bit higher with the 400 (?). You can also buy a stoker kit for the 400 to make a 461. I would personally build a th350 ahead of the th400 unless you are looking at very high HP/torque numbers. Th350 is easier to turn and less hp lost through drivetrain. I know a lot of people use 6x heads, 7k3 were off only 1972 400 (I had them on mine and seen they didn`t come on anything else. 96CC heads with large valves) I would buy an aluminum intake, but all the parts when building a motor have to work together good, or else motor can be a dog.

To choose a proper camshaft, you need to know vehicle weight, torque stall, gear ratio, etc.. that will be best for your situation. Also need to know about if street/strip, stip only car, etc..

Also need to do the math behind a compression ratio. A few things come into play when choosing the right compression. Aluminum vs cast iron heads, piston-(Dish, dome, flat top, amount of cc in valve relief...), camshaft specs like overlap, height above sea level, head CC`s, Static compression and dynamic compression.

For any build you will need bearings, gaskets, etc.. for a build. Unless you are doing a junkyard rebuild.

 

[1980Esprit]

PS: We will have about $5800-$6300 into our motor with a mild rebuild. Maybe around 375hp, 450 trq.

 

[cars-r-us]

Wow, just looking for help on witch parts are the best to use of the parts I have, didn't know I had to make 100.000 a year to join this forum, and be told if I don't spend big money, my motor is a junk yard motor!! Thanks for the help!

______________________________

 

[bsvowell1987]

If you are going with mostly stock parts, go with the 455. It has been reported to handle up to 700hp on a stock short block with 3.25 mains. The more displacement will give you more torque with out the big budget.

as far as the heads, 6x is the best with low compression for todays fuel. important thing is that you know what 6x heads you have. if they are 6x-4, use them. If they are 6x-8, don't wast your time, go with the 7k3. I would stay away from the 4x as they used press in studs.

As far as transmission, I always found manuals to be more fun to drive and muncie make good transmissions. If you insist on the automatic, go with the 350. Its cheaper to rebuild and handles all the power your motor will put out.

As far as intake, go with a 4 barrel. both 400 and 455 are going to need to breath. My 455 had a 650 and it sounded like it was sucking through a coffee straw so I put a 750 on it. I would recommend no smaller than 700.

 

[1980Esprit]

Hey I am sorry, I did NOT see the part about using your own parts.

-A junkyard motor is just a term used for when not doing any machine work or buying a bunch of new parts. Has nothing to do with being a junk motor.
-I am 16 so there is no way I can make 100k a year as well?
-You had asked for which camshaft would be great. If you are not going to spend big money, are you going to buy a new camshaft? Comp cam Xtreme energy creates higher cylinder pressures. That makes these cams great for low comp heads. I use 262XE that is best for street use.