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#1
11-01-2002, 08:14 AM
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OK guys I have heard that there are certain profiles that work best in long rod motors. I am getting ready to go from a flat tappet solid to a solid roller and am wondering what would work best for this combo. This is a strip only bracket car.
Bore/stroke: 4.21 X 4.25 Eagle Steel Rod length: 6.8 Custom light weight J&E pistons w/light pin Compression 12.0 TH-400 with Converter stall 4100 rpm 3.73's with 28" tire Heads #16's I-flow 295 cfm @.550 lift @28" h20 E-flow 190 cfm @.600 lift @28" h20 Car- A-Body 3700# race weight What do the prefessionals say? Tim C 65 LeMans 11.06@121
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Tim Corcoran |
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#2
11-01-2002, 08:14 AM
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OK guys I have heard that there are certain profiles that work best in long rod motors. I am getting ready to go from a flat tappet solid to a solid roller and am wondering what would work best for this combo. This is a strip only bracket car.
Bore/stroke: 4.21 X 4.25 Eagle Steel Rod length: 6.8 Custom light weight J&E pistons w/light pin Compression 12.0 TH-400 with Converter stall 4100 rpm 3.73's with 28" tire Heads #16's I-flow 295 cfm @.550 lift @28" h20 E-flow 190 cfm @.600 lift @28" h20 Car- A-Body 3700# race weight What do the prefessionals say? Tim C 65 LeMans 11.06@121
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Tim Corcoran |
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#3
11-01-2002, 08:55 AM
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Had the exact same motor in my GTO up untill recently. [img]/infopop/emoticons/icon_wink.gif[/img]
My Crower solid roller is for sale. Its barely used (6 passes and about 12 dyno pulls) and it would save you some cash. I don't have all the specs with me right now, but the lift is .660-.680 with a 1.6 rockers. Made 642HP with RAIV's that flow less than your heads do and the same compression. You didn't post the flow numbers for your heads at high lifts, but I would imagine as long as they don't drop way off, this would be an excellent cam for your motor. E-mail if interested and I'll get you all the specs from the card. "Do you love me? Do you hate me? Ready or not....Here....I......come....." Ja Rule |
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#4
11-01-2002, 09:42 AM
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Tim,who did the heads?295@28 at 550 lift is unbelievable!
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#5
11-01-2002, 09:43 AM
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Tim, my 462 combination had very similar #16 D-port heads, Victor intake and 926cfm Holley 750.
It seemed to like the Ultradyne 300/307R8, 264/271 @.050 on a 108LS, gross lift .689 w/1.65. Made peak power at 6400 rpm and peak torque at 4900 rpm on dyno. Car ran high 10's at about 3700 lb race weight. (complete specs on BIO) In addition to the opinions here consider calling Harold at Ultradyne, be persistant as he is hard to reach, or talk with Chris Mays at Comp Cams. Discuss something that will produce an optimal improvement within your desired rpm range in your particular engine. Off-the-shelf catalog cams are generally specced for a typical engine. 'Damn right it's a street car'
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
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#6
11-01-2002, 09:44 AM
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I personally don't think the difference between a 1.57 r/s ratio and a 1.6 r/s ratio is enough to change the cam needs.
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#7
11-01-2002, 12:58 PM
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Have you guys seen Pete's article on Rod Stroke ratios in the latest PE with Rodney Butlers twin
turbo car on the cover? Pete says that the 6.8 length rods are normally used because they are as strong as normal 6.625 aftermarket rods but cheaper. People buy them for that fact period. My opinion is that the rod connects the piston to the crank, period. I have seen 347 Fords with 3.4 stroke and 5.4 rods (RS=1.588) make 1800 hp at 9000 rpm. Bruce Crower says do not go over 1.75 R/S on a N/A motor and 2.0 R/S on a blower motor. This is because the blower motors normally do not need the displacement and the builders reduce the stroke of the crank for durability and strength and the rod has to be longer to hook up the crank to the piston therefore a bigger R/S ratio. Tom V. 
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#8
11-01-2002, 05:31 PM
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I run the same combo only with home ported 48's and 4.11's on a 31" tire. My 69 Goat weighs in at about 3900# race weight. Best ET so far was 10.89 on the motor and 9.89 on NOS. Cam was a Butler Ulradyne 268/274@.050, .626 lift, 1.5 rockers, lobe sep. 106, degreed in at 100. Runs real smooooth at the Coffee Shop! ... Eric
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Runner Up Q16 Norwalk 2013! |
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#9
11-02-2002, 01:16 AM
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Tom,
I read that article too, he makes it sound like engine builders are using the 6.8 rod and building the engine around it because its cheaper. From the article it leads me to believe he feels they are unnessary. But what I thought was interesting was the article he wrote in PE some time back. It was titled 'Building A Reliable 660-HP Pontiac 400 Bracket Engine' It outlines the engine Butler built for him for his '67 Firebird bracket car. They used 6.8 aluminum Super Rods.....hmmm, I guess I am confused, but it sounds like he is contradicting himself [img]/infopop/emoticons/icon_wink.gif[/img] 1967 GTO 400 4-speed (416) #62's 11:1 solid lifter 6.8 Eagle/Ross 11.87@115 (w/mufflers)-->so far!
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1967 GTO 416 5-spd streetcar 11's on HP low 10's 150 shot 1965 GTO 10-71 Littlefield high-helix retro/Bird (untuned) 8.44 @159 3500+lbs 10.5W's SOLD! 1964 421 GP-Sold 6.0 cert. Fiat bodied altered blown alcohol Pontiac IAII-Sold |
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#10
11-02-2002, 06:51 AM
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With casting #16 heads use a longer rod. Rod length is tied to intake volume and cam LSA. You have a limited intake volume cc with those #16 heads, I doubt it is even 190 cc. That could use a longer rod.
yes, Ford small blocks run a short rod, mainly because they have such a short deck height, that's all they can fit. But they also have much better cylinder heads than a Pontiac casting #16, that makes up for it. the Pontiac guys running low 8's now without NOS, are using long connecting rods...you can't argue with success... the original Pontiac 6.625" rod length was designed for the 1955 Pontiac 287 motor, that only had a 3.25" stroke. Do the R/S math on that one, it was over 2:1 R/S at the time. If it did't matter, why didn't they just use a shorter rod, and save money on material ?? hmmmm.... It was kept that length all those years until 1979, for cost purposes, not performance- good enough for a street car. FWIW, I have a hard time believing a ported #16 could flow those numbers on intake. What is your intake cc ?? |
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#11
11-02-2002, 08:28 AM
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Quote, "Use the longest damn connecting rod you can fit in the engine."
This came straight out of Smokey Yunick's mouth. Anyone want to contradict him? [img]/infopop/emoticons/icon_smile.gif[/img] "Run wild with an Indian, not with the crowd in a Chevy" "Have you driven your Pontiac over the Taliban lately?" 
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Less said,,,,,,,, Less mended. |
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#12
11-02-2002, 09:36 AM
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Tin I'd agrue with him..if he was alive.
I have to agree with Zedo and Pete. And 6.8 BBC aluminum rods are stock on the shelf item. I can live with the extra side clearance, Maybe Bruce can't. Bwahahahahahaha [img]/infopop/emoticons/icon_rolleyes.gif[/img] Pontiacs run a longer rod ratio then most anyway, if you compare B/S. Except the SBC. But I feel to many factors and different combos available are involve to answer this on the boards. But here's a for instance..... Longer rod with a higher pin height makes for a short skirt and lighter piston with less rotating mass. And the beat goes on. LOL. Yes, Cheaper way back when all you had to do was offset grind a crank .040 (2.200) and then use the 6.8 BBC :Cheaper" Eagle rod. Any custom piston is the same price. So go for it. But then again, I like and run a shorter rod combo then most. Hummmmmmmmmm. [img]/infopop/emoticons/icon_wink.gif[/img] [img]/infopop/emoticons/icon_wink.gif[/img] [img]/infopop/emoticons/icon_wink.gif[/img] [img]/infopop/emoticons/icon_biggrin.gif[/img] Depending on application. [img]/infopop/emoticons/icon_wink.gif[/img] We will match or beat anyone's "Current" catolog price on any Automotive related part. Give us a call. We build and learn from em all, but We "LOVE" Pontiacs!!! http://PontiacDude.cc |
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#13
11-02-2002, 09:44 AM
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#16 heads.............295@.550
Interesting. [img]/infopop/emoticons/icon_eek.gif[/img] Offset rockers ?????????? We will match or beat anyone's "Current" catolog price on any Automotive related part. Give us a call. We build and learn from em all, but We "LOVE" Pontiacs!!! http://PontiacDude.cc |
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#14
11-02-2002, 02:14 PM
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Here I am thinking all of this is mute, as them man already has a motor together...............
He wants a cam recommendation! "Do you love me? Do you hate me? Ready or not....Here....I......come....." Ja Rule |
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#15
11-02-2002, 02:20 PM
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<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by PONTIAC DUDE:
Tin I'd agrue with him..if he was alive.<HR></BLOCKQUOTE> You would lose. [img]/infopop/emoticons/icon_razz.gif[/img] See ya Saturday, then we can argue about it. hehe "Run wild with an Indian, not with the crowd in a Chevy" "Have you driven your Pontiac over the Taliban lately?"
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Less said,,,,,,,, Less mended. |
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#16
11-02-2002, 05:31 PM
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Tom S
Pete McCarthy ported the heads several years ago, probably over ten years ago probably at Gerry Goodale's shop. They also have Manely 2.19 intake valves. I bought the heads from Bill Takanabe who had them on his 10 second GTO, of course this car is a lot faster now. After I bought the heads they were flowed on Dave Bischop's Superflow 600 bench back when he had his shop in the same building as Pontiac Enthusiest. I did a small repair on them, machined the valve seats, installed new exhaust valves and new springs. When Pete saw the heads he remebered porting them and said he thought they still had more in them. He wanted to work more on the short turn but I couldn't leave them. Tim C. 65 LeMans, 3700lb. all steel, full interior, D-ports and a flat tappet cam, 11.06@122 [This message was edited by Tim Corcoran on November 02, 2002 at 07:54 PM.]
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Tim Corcoran |
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#17
11-02-2002, 05:57 PM
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Pontiac Dude
I think the average flow of the intakes is about 287. Some of the ports flow 290, I think I should of said 290 not 295. Tim C 65 LeMans, 3700lb. all steel, full interior, D-ports and a flat tappet cam, 11.06@122
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Tim Corcoran |
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#18
11-02-2002, 06:15 PM
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Tim,it was not the 290ish as much as the low 550 lift that is remarkable.I have had Pete and Dave both do work for me and THOSE numbers are remarkable.Tom
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#19
11-02-2002, 07:22 PM
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Posted:
"Heads #16's I-flow 295 cfm @.550 lift @28" h20" "E-flow 190 cfm @.600 lift @28" h20" The E-head does not sound right either as my almost untouched E-Heads flow 282 at .600 at 25" h2o. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#20
11-02-2002, 08:10 PM
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Tom, I think he means Exhaust (E) flow.
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