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BL72
Tribal Scout

USA
9 Posts

Posted - 22 Aug 2017 :  09:23:15 AM  Show Profile  Reply with Quote
Hey all,

New to this forum, tho I have been lurking for a long bit. I have a 72 firebird I have owned for 21 yrs. that's in the midst of frame up pro-touring rebuild.

I also have a 1968 firebird. Its a solid driver really nice and leads me to joining and asking some questions...

It has a 30 over 455 in it currently. Freshly rebuilt. Mild cam. I don't know how to post pics of the cam sheet. It has 6x-8 heads. It has TRW pistons. I m not sure how much power the car has but I believe it needs some top end work. It had a Pontiac intake and quadrajet (850?). manifolds and 2.5" exhaust and still has points ignition.

First, how do I get my cam sheet posted on here?
2nd, if I go with a 3" exhaust, dougs headers, northwind intake and MSD 6AL what could I expect? what carb?

I saw cliffR posted here abpout a block I feel may be close to what I have on the bottom end:
http://psp.aquacomp.net/topic.asp?TOPIC_ID=7061

Thanks for the help!
Phil

Phil
The Great White Buffalo

USA
7219 Posts

Posted - 22 Aug 2017 :  09:31:34 AM  Show Profile  Reply with Quote
Welcome Phil, regarding the 455 project, which car are you referring to (68 or 72)?

Lets get some more information on your plans and expectations but right off the bat I would delay any plans to buy the Intake, MSD and carb as what you have already is most likely the very best to begin with.

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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BL72
Tribal Scout

USA
9 Posts

Posted - 22 Aug 2017 :  09:39:23 AM  Show Profile  Reply with Quote
Thanks Phil! the 68 for this right here.

so the 68, I just want a mild street rod for now. I think it needs to breath better maybe? I'm not buying anything now or this year. planning for the spring really. I want to know if some bolts on can help with waking it up some is all.

Thanks
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tjs44
Cochise

USA
412 Posts

Posted - 22 Aug 2017 :  10:28:58 AM  Show Profile  Reply with Quote
HP is in the heads!You will need to kick up the flo to make meaning full HP.Headers on a street car can get you a few more over RA factory exhaust.A single plane intake wont get you much without the head flo.It is the combination of parts that will get you the most gains.Also the better the head the less cam needed to get you too your HP gains.Also remember with higher HP street ability goes down some like vac for power brakes and if a auto a need for more converter and lower rear gears.Tom
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cortcomp
Coyote

USA
5335 Posts

Posted - 22 Aug 2017 :  10:30:26 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Skip the MSD box for a pretty normal motor. Others have chased issues with them while tuning, i've personally seen some die and leave guys rideless waiting for parts, and i personally don't feel they add anything to your average street motor, not that my opinion carries much weight. Run an HEI, or if you want to look closer to stock a small body HEI or a pertronix like kit in your points dist.

I prefer the Ram Air headers as they look good, no interference issues, easy to install/remove, seal nice, and don't rust as easy as headers. I've used a few sets of them and i've been sold every time.

It sounds like you have a decent street combo, what issue do you feel you're chasing? General lack of power?
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BL72
Tribal Scout

USA
9 Posts

Posted - 22 Aug 2017 :  10:50:02 AM  Show Profile  Reply with Quote
yea it feels like there is plenty of Torque just not much power. Feels like there should be better accelerating to me. It has a 3.73 posi rear. T5 trans 5 speed. I don't know if maybe its the trans? at 60 mph, im at 2k RPM's and I can take off in 4th if I want.... I think it needs tuned or something or I don't know how to explain it.

It does have the pertronix in it, so that's a plus.

is there a way to post pictures?
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cortcomp
Coyote

USA
5335 Posts

Posted - 22 Aug 2017 :  11:23:42 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
You have to host pictures somewhere else (imgur or wherever everyone is using now). Then you get the link to it (http://sample.com/imagename.jpg).

When you click "reply to topic" (npt quick reply), you can insert an image, and between the img tags, you put the url, so like {img}http://sample.com/imagename.jpg{/img}
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tjs44
Cochise

USA
412 Posts

Posted - 22 Aug 2017 :  11:52:00 AM  Show Profile  Reply with Quote
What is the first gear in your T5?With the 3.73 rear and a 455 if lower than something like a 2.20 your not getting any pull in first gear.Tom
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BL72
Tribal Scout

USA
9 Posts

Posted - 22 Aug 2017 :  12:23:51 PM  Show Profile  Reply with Quote
honestly, Im not sure of the gear ratio. I know it was out of a 90s trans am is all.
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BL72
Tribal Scout

USA
9 Posts

Posted - 22 Aug 2017 :  12:27:42 PM  Show Profile  Reply with Quote
here is my cam sheet I hope lol

https://drive.google.com/file/d/0B-FfItea-63wTTJkZExmbldMWU0/view
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DanM
Buffalo

80 Posts

Posted - 22 Aug 2017 :  4:45:05 PM  Show Profile  Reply with Quote
Phil,

May I suggest you take more time to get a better understanding of what you have?

The T5 first gear will be 3.7ish. If you actually have 3.73 rear end then you have plenty of gearing to get the job done. In fact you should be able to roast your rear tires with very little effort with that rear end, 1st gear, and 455. Even if you have some crazy tall tire line a 275/75-15 which probably wouldn't fit in the wheel wells anyway.

Are you comfortable shifting near red-line? You're not going to get any real horsepower if you shift too soon. Remember HP = torque X RPM so if you shift at 2500 you will have half the HP (after you shift gears) compared to shifting at 5000.

Bolting on headers and not doing anything else will probably get you 5 - 10 HP. And that HP will be above 4000 rpm. Going from 2.5" to 3" exhaust without changing anything else will probably also get you 5 HP if that.

But if you port your heads, mill the heads to increase compression ratio, and use a cam with more duration, then the headers will be more useful.

In my opinion keep the Pontiac intake forever. Keep the quadrajet. Get the headers but pay a trusted mechanic to install them. Get a decent HEI but don't bother with the 6AL.

Until then, I'm guessing you have just under 290 HP at the rear wheels. That should be plenty for many miles of fun.

Go to the track.
Go to the dyno.

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

80 Posts

Posted - 22 Aug 2017 :  4:57:03 PM  Show Profile  Reply with Quote
What order should you make upgrades?

The headers and HEI won't do much alone but they will allow a more aggressive engine to reach its potential. If you get the headers first then upgrade the cam/heads you won't undo any of the work it took to install the headers, so no time wasted. And visa versa.

So, headers upgrade get's 5 HP. Cam/heads get's another 70.
vs
Cam/heads get 50 HP. Headers upgrade gets another 25 HP.

Either way you stand to gain 75 HP.

(numbers are approximate and examples only...)
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BL72
Tribal Scout

USA
9 Posts

Posted - 22 Aug 2017 :  6:30:47 PM  Show Profile  Reply with Quote
Thanks for all the great info guys!
So i talked to a guy about going on a Dyno and some tuning. Which ill do soon.

Is there one pontiac intake thats preferred to others? Ill check what i have.

Ill look at porting my heads and what cam wkuld be recommended?

What would be a safe redline? I believe the hood tac is low 5000's if i recall. But im not sure exactly and better safe than sorry
..

I did just get it and i do baby it probably a bit too much.


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cortcomp
Coyote

USA
5335 Posts

Posted - 22 Aug 2017 :  8:13:35 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
455 stock rods? 5000 safe bet. I've made some spurts past that but a nice long jaunt down the highway at high rpms can have you letting off the gas to hear a rap rap rap of a rod knock.
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BL72
Tribal Scout

USA
9 Posts

Posted - 23 Aug 2017 :  2:02:58 PM  Show Profile  Reply with Quote
Id almost bet they are stock.
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 24 Aug 2017 :  10:02:12 AM  Show Profile  Reply with Quote
Have you tuned your secondaries and ignition timing curve? How's it idle? That stuff can make a world of difference . A well tuned 350 can easily outperform a poorly tuned 455 for example.

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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BL72
Tribal Scout

USA
9 Posts

Posted - 24 Aug 2017 :  12:23:08 PM  Show Profile  Reply with Quote
I have not. Im hoping at the chassis dyno we can get all of that done
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BL72
Tribal Scout

USA
9 Posts

Posted - 24 Aug 2017 :  1:12:56 PM  Show Profile  Reply with Quote
I talked to kauffman about sending them my heads for porting & milling. He guesstimated 1000 to 1400 bux. Thats what a single high port cost. What kind of difference could i expect going with him machining my heads and the high ports? What else must be done if i went the high port route?
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Steve C.
Crazy Horse

1675 Posts

Posted - 24 Aug 2017 :  2:38:05 PM  Show Profile  Reply with Quote
High Port heads are overkill, unlikely you will need or take advantage of the reported 330 cfm as cast airflow or the large 277cc as cast runner volume. Also the large 2.200" diameter, and long length, valves with a tall 2.00" installed height will require special valve springs. Last they are called 'High Port' for a reason, they are taller and will add to hood clearance issues.


.

Edited by - Steve C. on 24 Aug 2017 2:44:45 PM
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Steve C.
Crazy Horse

1675 Posts

Posted - 24 Aug 2017 :  4:04:33 PM  Show Profile  Reply with Quote
Whatever cylinder heads and intake manifold you end up with it will be important to pay attent to gasket matching the intake to the cylinder heads. As a rule of thumb, you'd like to create a uninterrupted flow path for the intake into the cylinder head. More on the subject here:

http://www.arkansaspontiacs.org/techstories/gasketmatch/gasketmatch.pdf

I see the Northwind intake mentioned here, take note of the port exit dimension of that intake. It was first introduced to have a 2.300" port height. Since then it is my understanding it is now also available in a lower height to use a RAV size intake gasket. Two versions. The popular Felpro 1233, often touted as a RAIV size gasket, has a port height of about 2.200" tall, taller than a typical 'stock' size gasket. Often factory iron heads are not ported to this height, and some as cast unported aftermarket aluminium heads are not that tall. To further add fuel to the fire a High Port head as cast with no port work uses a taller intake gasket yet, about 2.320" tall. Well beyond most modified factory intakes.


.

Edited by - Steve C. on 24 Aug 2017 4:07:00 PM
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