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frankie
Buffalo

USA
62 Posts

Posted - 17 Aug 2016 :  8:07:18 PM  Show Profile  Reply with Quote
guys my 462 stroker has only 8 hg in. at idle and 20 hg in, at 2,000rpm

HOward cam is

Stock #: 410361-08

Camshaft Type: Hydraulic Flat Tappet
Duration Exhaust: 294
Duration Intake: 289
Duration at 050 Exhaust: 241
Duration at 050 Intake: 235
Engine: 265-455
Firing Order: 1-8-4-3-6-5-7-2
Intake Centerline: 104
Lobe Separation: 108
Engine Manufacturer: Pontiac
RPM Range: 2700 to 6500
Valve Lift Exhaust: .503

th 400 with headers and Barry grants 750 demon

should i go with a hydro boost or a vacuum pump?
Thanks
Frankie

Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 17 Aug 2016 :  9:57:09 PM  Show Profile  Reply with Quote
Yes.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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Phil
The Great White Buffalo

USA
7223 Posts

Posted - 17 Aug 2016 :  9:59:53 PM  Show Profile  Reply with Quote
How much tuning and dialing in have you done?

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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GtoGuy32
Cochise

USA
842 Posts

Posted - 18 Aug 2016 :  12:25:37 AM  Show Profile  Reply with Quote
What size booster are you running (diameter)?

I ran a cam with 236/242@ 0.050 duration and had great vacuum breaks. I had similar vacuum to you at idle and through the rpm range.

Make sure the check valve on the booster is working.

A vacuum can is a good start.

I just changed my cam to a 254/260@0.050 and now am running a hydroboost brake system.

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Phil
The Great White Buffalo

USA
7223 Posts

Posted - 18 Aug 2016 :  07:54:33 AM  Show Profile  Reply with Quote
And I am running a 230/242 cam (541 lift) with an HO Intake and an 800 Qjet. Plenty of power brake vacuum, idles decently at 800 and pulls strong and steady at 1200 in OD with the convertor locked up. My LSA is 112 though vs. your 108.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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frankie
Buffalo

USA
62 Posts

Posted - 18 Aug 2016 :  12:06:08 PM  Show Profile  Reply with Quote
guys it is a stock booster but i did put on wilwood calibers on the front that is larger then the stock ones. stock was single piston these are duel pistons
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GtoGuy32
Cochise

USA
842 Posts

Posted - 18 Aug 2016 :  5:57:24 PM  Show Profile  Reply with Quote
Did you change the proporsioning valve?
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Phil
The Great White Buffalo

USA
7223 Posts

Posted - 18 Aug 2016 :  8:14:11 PM  Show Profile  Reply with Quote
The piston size in the stock MC may no longer match the hydraulics required by the piston area of the new calipers.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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frankie
Buffalo

USA
62 Posts

Posted - 19 Aug 2016 :  01:38:07 AM  Show Profile  Reply with Quote
Phil i think your right about the size of the piston in the stock master cylinder. I am going to contact Wilwood and see what they say.
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Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 19 Aug 2016 :  11:17:20 AM  Show Profile  Reply with Quote
Cort installed a brake vacuum pump system. Off a VW IIRC.

IMO, trying to get a booster to work like factory with 235 intake duration AND a 108 LSA ain't gonna happen.

Its not that hard to drive around building enough vacuum on deceleration to charge the booster. But in a O-$HIT situation i would hate to have a hard and non-responsive brake pedal.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 19 Aug 2016 11:18:02 AM
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cortcomp
Coyote

USA
5339 Posts

Posted - 19 Aug 2016 :  2:06:23 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I did, audi pump and a vac can and lines all hidden inside fender/behind battery. You didn't really hear it unless you just turned key on. but brakes were already working OK for 1 or 2 stops or a single really hard stop. I wanted to make them like normal again, just add some reserve with the can and the pump to "top things off".

the hydraboost setup is great because you get great assist. I'm sure there are other issues like too much pressure or needing a restrictor or what not. Bear did one in his 69 that he loved IIRC.
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frankie
Buffalo

USA
62 Posts

Posted - 05 Jan 2017 :  8:24:08 PM  Show Profile  Reply with Quote
well guys the Astro's hydro booster did it for me!!!! I used it in place of the Vacuum booster, I took the vacuum booster's mounting bracket and added it to the Hydro booster. Used -6AN lines from the steering pump to the hydro and same size from hydro to the steering block,then tee'd in the return line with both power steering pump and Hydro's from the steering box.
All in all it cost me about $100 or less.
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cortcomp
Coyote

USA
5339 Posts

Posted - 05 Jan 2017 :  9:22:56 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Glad to hear it and thanks for detailing the parts for those that follow.
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Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 06 Jan 2017 :  11:07:48 AM  Show Profile  Reply with Quote
Nice.
How long did it take to fab up and install?
How do the brakes feel?


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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frankie
Buffalo

USA
62 Posts

Posted - 06 Jan 2017 :  11:39:22 PM  Show Profile  Reply with Quote
total was not that many hours. I took off the mount to the Vacuum booster and mounted it to the firewall. The bolt pattern of the Hydrobooster is the same as where the vacuum booster is rivet to the aft of the vacuum booster mounting bracket. Making two braided line and teeing in a 3/8 rubber return line took about an hour. so all in all about 2.5 hrs. The braking is great since I can now lock up the tires.. and I put on Wilwood disk brakes on the front to replace the one piston caliber that came stock. need to the rear now , I hate brake shoes but that will have to wait. I have discovered that I have created a monster when I stroke this engine. it needs more fuel, more exhaust, more and more air. I have a wife that hates this car that I have had since 1982. so spending money on it is always a challenge.
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Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 07 Jan 2017 :  11:02:11 AM  Show Profile  Reply with Quote
My wife did not like my 75 lemans till i had to rush her to the emergency room. Lots of pedaling to regain traction.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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DanM
Buffalo

80 Posts

Posted - 16 Feb 2017 :  12:02:25 PM  Show Profile  Reply with Quote
Lose the wife.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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NOTROD
Buffalo

USA
64 Posts

Posted - 16 Feb 2017 :  4:00:03 PM  Show Profile  Reply with Quote
quote:
Originally posted by DanM

Lose the wife.



That made me chuckle.
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Blued and Painted
Chief PONTIAC

USA
3409 Posts

Posted - 16 Feb 2017 :  7:49:58 PM  Show Profile  Reply with Quote
I had pushed the door as too close before she was completely out of the car.
The door latched with here pointing finger still in the jam. Then there was allot of screaming.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 16 Feb 2017 8:07:43 PM
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NOTROD
Buffalo

USA
64 Posts

Posted - 16 Feb 2017 :  9:18:41 PM  Show Profile  Reply with Quote
Yyyyow! That didn't make me chuckle. I watched my dad accidentally slam my brothers ring and pinky fingers in Dodge pickup tailgate when we were younger. It was one of those hard to close tailgates too, you really had to slam it. It was the craziest thing. When it happened all my brother said, in very calm and normal voice, was "ow, dad". Once his fingers were out, we started walking up to the house. About half way there he dropped like a rock, passed out cold.
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