[DonnyD]

yes. 10.5-1. sorry for not listing that

[i82much]

Originally Posted by napster

I thought the same thing when I had my 496 built for my '73 T/A with the same cam the OP has. @242/248 @112LSA. The car has a Wilwood brake system. 12.1 inch rotors with 6 piston calipers in the front and four piston in the back. Also has a Wilwood master cylinder and proportioning valve.

Stops on a dime.

4.25 stroke? is a 496 a 4.31 x 4.25 combo?

My pb are fine with OF in a 505, but that's a 236 @ .050 on a 112, 4.25 stroke.

[DonnyD]

Originally Posted by ta man

After rereading the OP posts,Family cruiser, run mid 11's and the wife drive it are the goals. I think the cam choice and compression ratio is key. The present combo may not like to run at 60mph in overdrive..less duration and higher compression in the 10.75 to 11 range would help. I personally would send the cam back, and find out your compression ratio and if need be shave the heads to achieve a higher ratio. My engine in my signature drives like a pussy cat and a similar build would be perfect. You would also get 20mpg plus.

its a 10.5-1 compression. Flat tops with the 87cc chambers. I may just swap out the cam, but now im kinda worried about vacuum and drivability. I guess you cant have the best of both worlds.

[b-man]

Manual brakes are fine if you’re worried about vacuum.

And there’s always hydroboost which a lot of guys like.

[napster]

Originally Posted by i82much

4.25 stroke? is a 496 a 4.31 x 4.25 combo?

My pb are fine with OF in a 505, but that's a 236 @ .050 on a 112, 4.25 stroke.

4.5 inch stroke in the 496 and stops great. Was going to go with 110LSA on the cam and was worried about vacuum. Changed to 112LSA and the brakes work great.

My GTO with the 461 has a 4.25 inch stroke with the same brakes as the '73 TA.
Only difference is the front & rear calipers are 4 piston. Also, stop on a dime. Cam is at 110LSA, 236/242 @ .050.

[Gary H]

I have a shop here in Jacksonville, Florida and do nothing but Pontiac's. We've built over 150 Pontiac engines. I think the combination you described is pretty good all the way around. Your vacuum with that cam will be fine. I might consider a 3:73 gear instead of the 3.50 with the 200r4 though. I have used several Art Carr 200r4 transmissions for customers behind engines similar to yours. They have held up well and the only issue is that they underestimate what the stall speed will be on their convertors. Their "2600-2800" convertor is actually around 3500 behind a healthy Pontiac engine. I actually have an Art Carr BUILT 200r4 on the shelf for sale if interested. Regarding the engine. Make sure that you degree the cam in at around 108 ICL and do use the 1.65 rockers. Also, try a 1" spacer on your intake. I recently put one on my street car and it picked up a tenth in the 1/4.

[jhein]

467 cid with 263/242 @ .050 on 112 LSA and I have about 14.5 vacuum at 750 rpm.

[ta man]

Originally Posted by DonnyD

its a 10.5-1 compression. Flat tops with the 87cc chambers. I may just swap out the cam, but now im kinda worried about vacuum and drivability. I guess you cant have the best of both worlds.

Sure you can,it's not the old days! You will get a hundred different opinions on cam choice..but the simple solution is go on the Butler site and pick another that has exactly the same valve lift..I've seen a few there when I looked so it will work with your current valvespring setup..something in that 235/245 range.

[Sun Tuned]

I knew an older fella that had a big red station wagon one time….

[DonnyD]

Originally Posted by ta man

I would have backed off on the duration to something like a 235/245 and in the 650 lift range. Would make the car more driveable. As far as the trans a well built 200r4 may last..a friend of mine uses Janis Transmission in Ohio...they have a great reputation with the Buick GN crowd and are a more dedicated shop than just a name on the transmission.
One question I have is what is your fuel system?

Going with a Holley sniper with their in tank fuel pump.

[DonnyD]

Originally Posted by Gary H

I have a shop here in Jacksonville, Florida and do nothing but Pontiac's. We've built over 150 Pontiac engines. I think the combination you described is pretty good all the way around. Your vacuum with that cam will be fine. I might consider a 3:73 gear instead of the 3.50 with the 200r4 though. I have used several Art Carr 200r4 transmissions for customers behind engines similar to yours. They have held up well and the only issue is that they underestimate what the stall speed will be on their convertors. Their "2600-2800" convertor is actually around 3500 behind a healthy Pontiac engine. I actually have an Art Carr BUILT 200r4 on the shelf for sale if interested. Regarding the engine. Make sure that you degree the cam in at around 108 ICL and do use the 1.65 rockers. Also, try a 1" spacer on your intake. I recently put one on my street car and it picked up a tenth in the 1/4.

I’ll let you know tomorrow about that 200r4. What’s your asking price on it? I appreciate all the great info. If I knew you guys existed, I would have certainly brought the engine to you.

[Gary H]

I'm building an engine for a customer in Tampa right now. Give me a call if you'd like. 904/868-9207

[68WarDog]

As Bman mentioned earlier. A little more cam put my heavy stock 70 GTO in the lower 7s 1/8 mile ( high 10s? Quarter) with a 254/262@.050. .582 lift sr with 1.5 HS. 315 Eheads, 10.8 cr 470. Continental 10" converter. 370 Ford 9".

[scott70]

I think a mid to low 11 sec 1/4 is doable. My 70 gto had a 455,,#62 heads ported to to 250 cfm,t2 intake,800 dp holley,ra4 sized cam with rhoads,3.73 rear with 10" jim hand converter,thm400.. Full exhaust. Rest of the car was all stock. .not stripped..PS,PDB. 3950+ lb with me in it Ran 11.7 at 115mph (7.4 1/8th mile) and actually was a mild combo. Definitely not as much as your engine.