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  #16 (permalink)  
Old 03-28-2013, 06:56 PM
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Quote:
Originally Posted by Mr. P-Body View Post
4.10s were never a Pontiac "factory" gear. T/As of that era with the 4-speed were usually 3.23s or 3.42s. The latter is the best for overall "street performance". Good accelleration and reasonable cruise RPM.

6Xs can be made to "work" on a 400. Milling about .040" off the -4s will yield right at 9:1. Get them "down" to about 88 CCs, 90 at the most (-8s are not suited to this, better left to the larger displacements). The exhaust valve should be upgraded to the 1.77" version. Porting should be done by someone that knows both porting AND Pontiacs. What makes a Chevy "turn on" may "kill" the power in the Pontiac. Jim Hand's "How to Build Max-performance Pontiac V8s" by SA Designs has VERY good porting detail.

With the manual trans, I would more recommend the XE274H over the 268. Still plenty of low-end and adequate vacuum, it will rev well past 5,500, where the 286 will be "all done" before that. If you REALLY wanna get silly, and make a 406 Pontiac a seathing monster, consider the XS series. We use SX274S in many 400s, along with the 6.8" Eagle rod. They routinely rev beyond 6,500 making power. NOTE: If someone tells you you "can't" rev a Pontiac, send them back to the '70s... Remember, when a Pontiac is running, it's making torque. It's very difficult to "hurt" the low-end. Add that to the power peak above 6,500 and you have a very strong street engine with a BROAD power band. I highly advise AGAINST the "K-Kit'. It contains the "wrong" timing set AND valve stem seals. Oh, they "fit", but they're not the ones we would use if building an engine for a customer. The timing set is the cheaper "2112", where the 3112 is called for ("true" roller, not a glorified bicycle chain). The Teflon seals are okay for a race engine, but we use Viton in street engines today. Also, there are other spring providers that have good offerings for the "odd" heights the Pontiac calls for. Reports on the Comp 995 have been spotty.

IMO, the best intake for the 400 is the RPM. This presents a hood issue, as you said. Larry Navarro of WFO Enterprises makes a "drop base" air cleaner housing for this purpose. It allows the use of the "shaker" AND a good intake. I would also recommend the AED 750HO or HOM carb. An MSD "Pro Billet" will cap it off. This combo is well over 400 HP and around 475-500 lbs. of torque.

There will be plenty other "opinions" on this. You will be advised to forget the smaller engine and "stroke" it to 461 or bigger. Good advice, but not MANDETORY. 400 is the engine that made GTO famous, and it wasn't famous for getting beat... A 400 is no punk when properly prepared. Vinny Meyeda goes 6.90s over 200 with a stock-block/crank 406 in his Probe F/C.

Jim

The 4.10 gears were added and need to go at some point, thinking 3.42. Other than budget would a stroker kit be better? What advantage does a built non stroker have? I really fear blowing off my budget if I go with a stroker and slowing down the restoration of the rest of the car. With a stroker I know I will want kre or e heads to get the most out of it. I also don't want so much motor and power that I can't afford to drive it with poor mpg.

I like the 400hp combo you suggest and sent a pm for more info.

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  #17 (permalink)  
Old 03-28-2013, 07:09 PM
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Is the porting that hard? I have read the book and whatever else I could find on porting d port heads. I'm a millwright so I do have die grinder and carbide bits and stones to get started. I can also turn down a few old valves at work for the patterns suggested in the book. With out sending the heads out and paying big money I would rather buy aluminum heads or lower my expectations for power.
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Old 03-28-2013, 07:15 PM
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Time spent on porting cast heads is well spent . It will also be more fun than the overtime you will be working to pay for the aluminum heads...LOL
I have another 400 block that is virgin I am saving for a later time that I am planning on building a street stroker out of. I have a " mild 389" right now that is near completion for the time being.
The stock 350 2 barrel in the car now will be mothballed....maybe I will find a deal on a LeMans Sport to put it in...
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Old 03-28-2013, 09:34 PM
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I agree about the overtime. Been getting enough of it lately but it will help. I want to do as much as I can on the car myself, not just to save money though. I can see the addiction. I looked at a 66 lemans a week ago and was happy it was too far gone for me. I need to stick to one at a time!
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Old 03-28-2013, 09:45 PM
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Originally Posted by 76TAmatt View Post
Sorry, I had it in the title but forgot to mention in the message that it is a 400 that I want to have bored .30 over...so about a 406?
I don't want to burst anyone bubble, but in '75 and '76 Pontiac cast an inferior block that was thin in the main webbing. That block had a casting number of 500557, so if that is what you have I'd advise that you don't put too much money in it. The casting number can be found on the lip behind and below the passenger side head as shown in this picture:

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Old 03-28-2013, 09:54 PM
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I found a 74 400 motor for $150 that I am going to buy, if the block is better than mine. All I know is it was from a station wagon or something. Has 4X small valve heads and 2bbl carb. I seen the "74" as shown in your picture but did not check the other casting numbers
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Old 03-28-2013, 10:17 PM
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My picture is a little decieving because that is actually a '74 350 HO block that was cast in '77. (Long story!) Before you trash your block, be sure you get the actual casting number because they chaged to a better block at some time.

Bill
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Old 03-28-2013, 10:46 PM
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I will check it this weekend. If nothing else I will save it for a milder build.
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Old 03-29-2013, 06:11 PM
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Quote:
Originally Posted by 76TAmatt View Post
I agree about the overtime. Been getting enough of it lately but it will help. I want to do as much as I can on the car myself, not just to save money though. I can see the addiction. I looked at a 66 lemans a week ago and was happy it was too far gone for me. I need to stick to one at a time!
You are a true PONTIAC GUY. The only reason you dont have 2 of them is that the one is too far gone.....ME TOO. LOL
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Old 03-29-2013, 06:17 PM
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Lol...yep. I own a G6 too
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Old 03-29-2013, 06:42 PM
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Lol...yep. I own a G6 too
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