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#1
03-22-2022, 05:20 PM
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New Engine Combination for '78 T/A
I have a '78 T/A currently with a 406 with 6X#4 heads 9.45 to 1, with the Comp XE274H-10 cam and last Doug's headers with 1 7/8th primaries and 3" collectors. Also, has 1.5 roller tip rockers. Behind it is a TCI 700R4 with 3.73's. I'm thinking of changing the engine as follows:
Put a 427 stroker kit in it for 433 cubes. Use a set of #48 heads with 9.9 to 1 compression. One of two cams will be used that I have still in the box from Butler Performance. Both are custom grind for Butler. First is HR with 230/236 @.050, LSA @ 112. Second is HR with 236/242 @ .050, LSA @ 112. I like the second one with 1.65 roller rockers. Will use the same headers, Transmission and Rear. Opinions and guesses on HP/TQ. Will not be for racing. Thanks in advance. Last edited by napster; 03-22-2022 at 05:45 PM. |
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#2
03-23-2022, 07:39 AM
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Unless you do some work on those heads BEST your going to get MIGHT be 420/450 hp or tq....gotta move air to make it happen.
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| The Following User Says Thank You to 67Fbird For This Useful Post: | ||
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#3
03-23-2022, 02:14 PM
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The 4.25 stroker cranks are the same price or less, might as well go big.
Totally agree on the heads, you can get the speedmaster ones if you're on a budget. .
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
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#4
03-23-2022, 02:24 PM
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How much lift will you have with the 1.65 on either cam, or at least state how much lift either cam has with 1.5 rockers.
If you going for a true 9.9 comp with iron heads I would run the bigger cam.
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I do stuff for reasons. |
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#5
03-23-2022, 02:38 PM
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Here are the cam cards.
There is a budget and I want to use the heads I have. Porting will be done, but to what extent needs to be discussed with the engine builder. |
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#6
03-23-2022, 04:49 PM
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Attached are dyno sheets from two engines, both are 455's. First is 8.8 to 1 compression with Super Duty heads, the second is just under 10 to 1 with iron "D" ports. The first dyno run is the smaller 230/236/112 HR, the second is the larger one. The third pic is the cam I used in the first engine. It is going to be the same as the Butler HR cam.
I don't think you'd be off that much in power with the 428 based build topped with #48 heads.......
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), Last edited by Cliff R; 03-23-2022 at 05:01 PM. |
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#7
03-23-2022, 05:13 PM
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The valve lift limit with the stock valve installed height of those # 48 heads is .480”.
Both of cam picks of yours even just with 1.5 rockers no less 1.65 rockers calls for having the spring pockets cut deeper for more installed height or new taller valves to be used.
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I do stuff for reasons. Last edited by 25stevem; 03-23-2022 at 05:19 PM. |
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#8
03-23-2022, 05:26 PM
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Cliff and Steve,
Thanks for the information. Very helpful. Jim |
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#9
03-23-2022, 05:34 PM
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Welcome!
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I do stuff for reasons. |
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