[gtofreek]

The 407 in the 67 GTO I mentioned above is very streetable for the power it makes. Idles nice in gear, starts right up, has a Continental converter that drives like a stock converter until you get on it, and it has a Gear Vendors OD unit in it. It's very responsive at any RPM and is very fun to drive.

[Young Pontiac Guy]

Great responses, thanks to all.

My goals: fun street car that runs low 13/high 12s. Car is 4 speed Bird. Fine with reving to 6000rpm. Dont really want to drop the extra couple grand on doing a stroker, plainly. Plan on using my stock intake which is Felpro gasket matched and cleaned up, Qjet, etc. Car has a 2.56 rear gear currently but looking to remedy that over the winter as well with a 3.08/3.23 (dont have yet).

Would likely go with KRE 310 DPorts. They are close to me here in Ohio.

How would the car be from 2000rpm on up with a set up like this?

[Dave Bisschop]

Originally Posted by Young Pontiac Guy

Great responses, thanks to all.

My goals: fun street car that runs low 13/high 12s. Car is 4 speed Bird. Fine with reving to 6000rpm. Dont really want to drop the extra couple grand on doing a stroker, plainly. Plan on using my stock intake which is Felpro gasket matched and cleaned up, Qjet, etc. Car has a 2.56 rear gear currently but looking to remedy that over the winter as well with a 3.08/3.23 (dont have yet).

Would likely go with KRE 310 DPorts. They are close to me here in Ohio.

How would the car be from 2000rpm on up with a set up like this?

We've built many 400 combo's over the years, we use to run a 413ci cast iron headed (265cfm) engine in our 3600lb 65 GTO which ran 10.20's @ 130mph. I love the 400 combo's but they are a bit more sensative to having the gearing (conv. if auto) matched correctly with the engine combo, not saying it isn't important with the 455 or stroker combo's but the bigger torque of the longer stroke can overcome a lack of conv. stall or rearend gear and still perform very well.

If your plan is to run 3.08-3.23 rearend gears along with a stock intake then I'd suggest a 290-295cfm max as the higher flowing head with it's larger port entrance won't match the OE intake vary well and the larger cross section will push the power curve higher in the rpm range which will be better complimented by a longer duration cam which won't work very well with the modest rear gear you plan to run.

Years ago we set up a customer with a 73 Formula, factory 4 speed and 3.42 gears, with a set of mildly ported 4X heads (225-230cfm) and a Summit 2801 cam. He bolted these on to a basic 406 shortblock which yielded 8.5 to 1 compression for 87 octane daily driver usage and for exhaust he had RA exh manifolds with 2.5" pipes. He used a stock intake with a Q-jet that he tuned and the car on regular street radial tires (read traction impaired) laid down 13.40's @ 105-106mph and he reported fuel ecomony in the mid teens as this car was used as a daily driver.

Here's a link to another one of our customers we built a 400 combo for http://www.sdperformance.com/custome...01.php?carID=9 obviously he has a bunch more rear gear and a 5 speed trans but it gives you an idea what can be done with 290ish cfm cylinder head on a 400 combo.

You won't have a problem reaching your goals, just keep in mind bigger isn't always better when it comes to cams and heads. The stock intake with a bit of work is an excellent choice. Get in touch with Cliff Ruggles for some tuning parts for your Q-jet.

We got my 17 year old son Zac out to the track this year in a borrowed 67 Lemans (ran out of time to get our 65 Tempest together), we took a runner 400 shortblock with 40,000 original miles on it (never been apart since Pontiac put it together), Old Crower 224/228 112 lobe sep cam, bolted on a set of 250cfm cast iron heads (9 to 1 compression), prepped iron intake and a 750 Q-jet with a Cliff's tune up in it and the car ran 12.68 @ 106mph with a 3.73 rear gear and a 3500ish stall, leaving the car in drive (column shift) and no tach so it was short shifting big time.

What type of camshaft were you planning to run? (flat tappet or roller)

What is your plans for exhaust system?

Dave

[Young Pontiac Guy]

I really appreciate the comments. Especially not trying to veer me toward a stroker kit.

I would like to run a flat tappet cam. I currently run a 2802 cam in my 670, ported head 400. It was a very budget minded build- just a rering, stock rods/pistons etc. This time looking to do forged piston setup. I am aware that I will likely want more lift than the 2802 offers. Any suggestions are appreciated as to cam, rockers, etc. Like the Crower stuff but open to other suggestions.

[Dave Bisschop]

Originally Posted by Young Pontiac Guy

I really appreciate the comments. Especially not trying to veer me toward a stroker kit.

I would like to run a flat tappet cam. I currently run a 2802 cam in my 670, ported head 400. It was a very budget minded build- just a rering, stock rods/pistons etc. This time looking to do forged piston setup. I am aware that I will likely want more lift than the 2802 offers. Any suggestions are appreciated as to cam, rockers, etc. Like the Crower stuff but open to other suggestions.

It comes down to personal preference, it's hard to argue with more displacement especially for a heavy street car, but a properly designed 400 combo will put many 455 and strokers to shame.

Do you have any flow data on your current 670's?

You won't want to go much bigger on duration than the 2802 cam with the rear gearing you have planned, the Crower 60243 would be something to consider along with 1.65 rockers. You'll want to keep the overlap in check especially with a manual trans. otherwise you won't have much fun trying to cruise around at lower speeds as it will want to buck.

Personally if you have a decent set of heads already, if it was me I think I'd look at investing the money into a 5 speed overdrive transmission and up the rearend gear to probably 3.90's. The performance gains you'd make with that and the increased fun factor would no doubt exceed the real world performance any head or cam upgrade you could make with a stock 4 speed and 3.08 to 3.23 gears.

Use as light of a piston as you can and for a forged rod the Eagle H-beams are hard to beat for reduced weight and strength.

I learned early on to make these 400's last turning some rpm with the stock cast cranks reducing the weight of the rotating assembly was huge. My first race 400 had 540 gram JE pistons and fairly heavy Crower rods. It hung together pretty well until we started turning over 7000rpm. After that we went to 412 gram JE pistons and aluminum rods, which held up very well even tagging the limiter in the burnout box at 8200rpm probably a few too many times!! We sure surprised the local crowd with their "Pontiac's can't rev" attitude!!LOL

It's your choice of course but I think you might want to consider the 5 speed idea, I've never had a customer regret that investment from a pure driving enjoyment standpoint.

Dave

[Young Pontiac Guy]

No port numbers, just a visual "big hog job" done a long time ago!

Exhaust is already headers, H-crossover, flowmasters. 2 1/2in exhaust.

Not a bad idea on 5 speed and some gearing. Just doesnt solve my rev problem! I take it to 5200rpm currently (pertronix with built in rev limiter). I hit it doing burnouts regularly. As well, typically dont wind it over 4800-5000 when shifting hard.

[Dave Bisschop]

Originally Posted by Young Pontiac Guy

No port numbers, just a visual "big hog job" done a long time ago!

Exhaust is already headers, H-crossover, flowmasters. 2 1/2in exhaust.

Not a bad idea on 5 speed and some gearing. Just doesnt solve my rev problem! I take it to 5200rpm currently (pertronix with built in rev limiter). I hit it doing burnouts regularly. As well, typically dont wind it over 4800-5000 when shifting hard.

I'm not suggesting you don't build a better shortblock, I'm just suggesting instead of buying aluminum heads put the money into a 5 speed. My 670's on our race 400 flowed 265-270cfm and the engine made peak power at 6800rpm (carried the power to 7800rpm on the dyno), granted we ran a large solid roller and a heavily modified Warrior intake with a 1050 Dom. carb., but if your heads flow 240-250cfm with a bit more cam you will have a combo that will pull hard to 6500rpm and make peak hp around 6000rpm.

Dave