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 Low-budget, Low-Compression, Low-Lift 455 project
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Lee
Sitting Bull

126 Posts

Posted - 18 Dec 2017 :  3:33:49 PM  Show Profile  Visit Lee's Homepage  Reply with Quote
I've been hot rodding for close to 40 years now, drag racing for over 30, and been around Pontiacs for virtually my entire life (I'm 51, btw). One trend I've seen getting worse (IMHO) is pushing "race" type parts and builds on people who are really needing "solid, reliable street" builds.

Granted, most of Pontiacs have been street/strip builds, and have been heavily tilted towards the race end. But my current budget and needs for my "new" Pontiac ('73 Firebird, cloned into a Trans Am) are directing me towards a path less travelled.

My wife enjoys riding in this car. I first installed a set of Year One 17" Rally II wheels. Next I updated the A/C with a Sanden compressor, parallel flow condenser, 134a spec POA and expansion valve, so I can cruise comfortably in the Texas summer heat.

Last year, I picked up a $500 455 cont.

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com

Lee
Sitting Bull

126 Posts

Posted - 18 Dec 2017 :  4:07:08 PM  Show Profile  Visit Lee's Homepage  Reply with Quote
The $500 455 turned out to be a complete engine, carb to pan and some accessories. It also included a THM 400, extra starter motor, and a few other things! The seller stated that the engine had been rebuilt up north, where his brother lived, then they shipped the car down here. It started and ran o.k., but "blew oil everywhere" when driven on the highway. I knew I'd need to take it apart, but did not then have a clear plan for what I was going to do with it.

Upon teardown I found the valley pan gasket was mis-installed, with a 1" gap for crankcase pressure (and oil) to blow out of. I also found the ring gaps were WAY bigger than they should have been - up to 0.150" gap on some that I measured! The camshaft was a CompCam 268, the old single-pattern design with .454" valve lift. The cam and lifters were in perfect shape, so I knew the valvesprings were well matched to this sort of cam. I still did not have a clear plan for the motor, though.

Meanwhile, the old 350 Pontiac was still running smoothly in the car, I just had a bad taste in my mouth from having something that LOOKED like a '73 Trans Am, but only had a 350 in it! I put it on my chassis dyno before I did anything to the motor, and it put a whopping 160-something HP to the wheels! I played around with the timing and carb, and got "up" to about 185rwhp - better, but still rather sad.

By last summer, I was ready to get the 455 installed. I cc'ed the heads (# 66's) and was sad at the HUGE chambers. My pistons were all (on average) 0.022" down the hole, and the pistons have the chamfered edges making the CR even lower. Compression calculated to a bit over 7.8:1! Even worse, the heads had pressed in rocker studs.

I WANT a set of heads from Dave Bischopp, and I also want an IAII block with about 535 inches, but those are still not in the budget... Hmmm, maybe do something different?

cont.

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com
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Lee
Sitting Bull

126 Posts

Posted - 18 Dec 2017 :  4:24:29 PM  Show Profile  Visit Lee's Homepage  Reply with Quote
I've been designing custom cams for a long time, and started using some engine modeling software several years ago. With the software, I've designed some very different, yet VERY effective cam designs for LS engines. I've also used it for several Pontiac cams that have ran very well. So I decided to see what sort of design it would show best for a much milder motor.

With high compression ratios, you have to worry about creating too much dynamic compression, causing the engine to experience detonation. But with only 7.8:1, I don't have that limitation. I didn't want to mess with the heads, and also worried about the pressed-in studs - since the previous cam had been fine with .454" valve lift, I decided I would use LESS lift so that no changes would be needed.

I ended up with 222/242 @ .050" lift duration, .443/.435 valve lift, 116 LSA and installed at a 112 degree ICL, custom ground by Bullet Cams. Look all you wish, you won't find anything like it in any catalog!

I installed new rings on the existing pistons, did a quickie home-hone job on the cylinders, new rod bearings, and a new oil pump. I used the Performer intake and Q-jet that had been on the 350, along with the HEI and log exhaust manifolds from the 350. I had to richen the idle mixture screws a bit, but otherwise it ran fairly well.

The exhaust system had the stock head pipes coming off the manifolds, then 2.5" pipe sloppily welded to the old head pipes and feeding into 3" Flowmaster mufflers, with another sloppy transition into 2.25" tailpipes (which rattle annoyingly at idle).

Back on the chassis, I was at 220rwhp right off the bat. Playing with timing and metering rods got me to 225hp at about 4,000rpm. Peak TQ reading was 310, but that is a bit misleading as I couldn't go to full throttle below around 3500rpm, or else the transmission would downshift.

cont.

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com

Edited by - Lee on 18 Dec 2017 8:06:51 PM
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Lee
Sitting Bull

126 Posts

Posted - 18 Dec 2017 :  4:50:48 PM  Show Profile  Visit Lee's Homepage  Reply with Quote
I had picked up a set of killer headers from forum member Steve Coombes. I got those headers with the intentions of a big HP motor with the Dave B. heads, not a low-compression stock headed budget motor. As time arrived to saw off the old headpipes and install headers, I got cold feet :-)

BIG primary pipes, reduced ground clearance,... Hmmm... I made some calls and sent some messages, and located a set of Tribal tri-Y's that were built and ready to ship - I bought them.

I had to cut the "ears" off of my transmission, in order to install them. Once that was done, they went on rather easily. I used the ARP header bolts with the extra-small 5/16" socket head, to make it easier to get a wrench on all of them (NOTE: get the 1" long bolts, the 3/4" bolts will only have about 3-threads that engage).

I am planning on replacing the pipes and mufflers, but wanted to see what sort of difference JUST the headers would make. I used some parts-store reducers to connect the 3" collectors to the 2.5" pipes, tacking it all together with my wire-feed welder while laying on my back (ugly welds, but it works!).

Although there were some exhaust leaks when I started it, it sounded better. Driving it around, if seemed to feel stronger - but I've learned over the decades that most butt-dyno's are poorly calibrated.

I finally got it back on the chassis dyno. First pull, no changes to the carb, and it put 265hp to the wheels! Power band was higher everywhere, and pulled to a higher rpm as well. Richened the carb with some thinner metering rods, and got 270rwhp and 345tq. So 45hp and 35tq improvements, when looking at peak values. More telling about the improvement of the header, however, was at 4500 rpm the motor was making 55ft-lb more torque than with the manifolds!

Even with the stock torque converter, traction is very limited and throttle response is immediate. The motor runs fine on the cheapest gasoline I can find. I've been driving fairly often recently, and it is very reliable. I'm using 3qt.s of CompCams 15W-50 break-in oil (high zinc) mixed with 3qt. of 20W-50 conventional Castrol, and the low-lift mild lobes should give me long life for the cam and lifters.

I'm scheduled to have my exhaust guru install all 3" pipe and Borla mufflers next week. I believe I will find even more power with those parts in place. A FAST XFI Sportsman efi system will be installed after the exhaust is done.

Will I break into the 300+rwhp zone??? I also plan on testing some different intake manifolds as well, after the EFI system is sorted out. Then, sometime next year, I hope to get it to the track and see what it will do :-)

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com

Edited by - Lee on 18 Dec 2017 8:13:25 PM
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Maurice Hood
Tribal Scout

USA
6 Posts

Posted - 18 Dec 2017 :  6:45:56 PM  Show Profile  Reply with Quote
Lee, I enjoyed reading about the buildup of your Firebird. Well written and informative, keep the information coming.
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Blued and Painted
Chief PONTIAC

USA
3432 Posts

Posted - 19 Dec 2017 :  11:17:22 AM  Show Profile  Reply with Quote
Subscribe !!


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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ta man
Two Feathers

Canada
36 Posts

Posted - 19 Dec 2017 :  2:33:33 PM  Show Profile  Reply with Quote
Good stuff...I agree ..I often see over built street car build ups for guys who just want to cruise.I'm trying to steer my son in that path. He sees my car SD heads hyd roller cam fuel system..etc.
I tell him you have to start at the basics..and with our Pontiacs basic is pretty good.I'm trying to teach him what can be interchanged rather cheaply..instead of the "Stroker/Aluminum head/Roller Cam mentality.

I should have taken my old 76 455 4 speed to the track with under 8 for compression it was rather impressive just with headers and a good 2.5 inch exhaust system.

1980 Trans Am
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Lee
Sitting Bull

126 Posts

Posted - 19 Dec 2017 :  5:45:37 PM  Show Profile  Visit Lee's Homepage  Reply with Quote
Thanks guys :-)

There used to be a summary of how my old '67 Firebird went from running 12.3's to running 11.2's using the same heads, shortblock, headers, intake, and carb. I don't remember where I posted it, or where it went to. Maybe I can keep this project documented on here. Maybe I can eventually catch up to TA Man ;-)

Oh, my EFI system shipped today 8-D

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com
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Phil
The Great White Buffalo

USA
7236 Posts

Posted - 20 Dec 2017 :  09:24:05 AM  Show Profile  Reply with Quote
Nice thread Lee. If the spirit moves you, perhaps you would consider doing a separate thread for the AC work as it could be quite useful to some of us wanting to keep AC but needing to do some sensible upgrades. I know I have a 74 which will definitely keep AC but needs some work on the system and a 79 and 80 as possible candidates down the road as well.

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.

Edited by - Phil on 20 Dec 2017 09:25:43 AM
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ta man
Two Feathers

Canada
36 Posts

Posted - 20 Dec 2017 :  10:15:32 PM  Show Profile  Reply with Quote
Lee one thing I've always enjoyed in this hobby is watching others tune their combination of parts.Over a span of 6 years I did something similar went from low 12's 114mph to 11.0's 123mph,same heads,intake,carb,cam ,exhaust,convertor..Its amazing what one learns in the process.Plus its all out there for others to learn.I know for sure Jim Hand influenced my way of thinking and tuning..

1980 Trans Am
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Bill Boyle
Horse Feathers (Charter Member)

USA
4869 Posts

Posted - 21 Dec 2017 :  04:58:06 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Jim Hand's influence on the Pontiac community and hobby is stupendous.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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phil400
Cochise

Canada
466 Posts

Posted - 21 Dec 2017 :  07:42:47 AM  Show Profile  Reply with Quote
I?m very much enjoying this thread, and this way of thinking, not everyone has 6-10k to spend on an engine. And parts availablility can be an issue for others. Working with what ya got, great Idea.

78T/A 4-SPEED Marty blue 400/milled 6x-4's/268H,comp roller tip rockers/ performer Q-jet/RA manifolds 2.25" exhaust with x-pipe/ mine since '99 3rd & final owner as long as I'm alive.
77 T/A sold
85 Monte Carlo sold
83 Mustang GT sold
"Let me tell you what Melba toast is packing"
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Lee
Sitting Bull

126 Posts

Posted - 21 Dec 2017 :  10:09:50 AM  Show Profile  Visit Lee's Homepage  Reply with Quote
quote:
Originally posted by ta man

I know for sure Jim Hand influenced my way of thinking and tuning..



I'm rather proud to be able to say that I was one of the first people to recognize who Jim Hand was, when he started posting on the internet a bit over 20 years ago :-)

Just a few days ago, I was cleaning up my office. In with some of my reference binders was a manila envelope, sent to me from Jim Hand in 1997. He had analyzed my Firebird's engine combination with his engine modeling software (I currently use a newer version of the same software) and offered suggestions to further improve my performance.

Heck, if anyone has read the Popular HotRodding article on my old Falcon wagon, I specifically mention Jim's influence in the write up! Even though I was building a Ford, I was using thoughts on torque, gearing, and overall powerband that I had learned from playing with Pontiacs and discussing things with Jim.

Phil, thanks! In all honesty, I COULD pull money out of savings or just carry some credit card debt and build the $10k engine that I REALLY want in the car. But I make a little money off of selling cams, dyno tuning, and other such "car stuff" and my goal is to keep this hobby "cost neutral."

I've now hit 270rwhp, and am a bit surprised! So, no I'm committed to this project :-) The new exhaust goes on next week (if my exhaust guy has time, he is retired and does this stuff out of his house now). The new EFI system should be delivered later today, but I'll wait until I have the exhaust on and have dyno tested it - I'm really trying to show the power gains (or lack thereof) with each change.

I have ideas for a few other dyno tests as well, but those will be down the road

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com
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NOTROD
Two Feathers

USA
71 Posts

Posted - 23 Dec 2017 :  11:46:29 AM  Show Profile  Reply with Quote
Great thread! Reminds me of the hours spent years ago scouring the salvage yards looking for carbs, intakes, heads, distributors, etc. Catalogs where only used for hot cams, headers and such.
I totally understand your "butt dyno" poor calibration comment, but with a street only build the "butt dyno" is all that matters if you ask me. A person can spend a grand to pick up a few tenths at the track and the car will feel no different on the street. In some case it might even feel slower.
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Lee
Sitting Bull

126 Posts

Posted - 23 Dec 2017 :  11:57:32 AM  Show Profile  Visit Lee's Homepage  Reply with Quote
quote:
Originally posted by NOTROD

Great thread! Reminds me of the hours spent years ago scouring the salvage yards looking for carbs, intakes, heads, distributors, etc. Catalogs where only used for hot cams, headers and such.
I totally understand your "butt dyno" poor calibration comment, but with a street only build the "butt dyno" is all that matters if you ask me. A person can spend a grand to pick up a few tenths at the track and the car will feel no different on the street. In some case it might even feel slower.



I have a great example of that! Back in '05 I had grown tired of my 3" Flowmasters. They were old when I got the car, and I had it for 10 years at that point. I talked with Tom Hand, and he sent me a set of large-case Goerlich Xlerator mufflers. There were a bit too big, so my part of the deal was to cut sections out of the case and weld-in patches so that they would fit the car. I also took pictures and sent them and test data back to Tom.

Those mufflers made the car WAAAYYY quieter! Shockingly more quiet. Just the noise reduction made me "sure" that I must have lost at least 20hp. First trip to the track with the new mufflers, and the car ran nearly a tenth quicker and over a full MPH faster!

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com
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Matt H
Cochise

USA
313 Posts

Posted - 03 Jan 2018 :  11:44:53 PM  Show Profile  Visit Matt H's Homepage  Reply with Quote
Lee- I am on board with your project. I just finished reading what you have done and am interested to see where you go with this. Interesting to say that the headers a huge bang for the buck ...40 rwhp. Impressive. Also how restrictive the log manifolds are.

1993 Firehawk # 118 sold after 7 yrs 309 rwhp / 342 rwtq
1979 Trans Am 400 4speed sold after 17 yrs -completly restored to is former glory by the new owner / then sold for big $$$$$
1981 Trans Am Turbo Pace Car 461 Stroker with iron heads - current car

Matt H

Edited by - Matt H on 03 Jan 2018 11:54:05 PM
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Lee
Sitting Bull

126 Posts

Posted - 04 Jan 2018 :  09:21:21 AM  Show Profile  Visit Lee's Homepage  Reply with Quote
Thanks Matt :-) I believe the rwhp gain is even more impressive, if you think of it in terms of percentage. Basically a 20% gain.

I was incorrect in 3rd post at the top. The tailpipes were actually just 2.0"! With the car on the lift at the muffler shop, I got a better view of everything. My muffler guy had to order some parts to get the system they way he wanted, so I don't have it back yet. But I'm VERY anxious to get it back and on the dyno!

My FAST Sportsman XFI EFI system is quietly waiting to be installed. After I dyno the new exhaust system, I'll start on the EFI install.

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com
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