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Thread: Big Cam for TBI

  1. #46
    Fuel Injected!
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    Quote Originally Posted by xtreamvette69 View Post
    2500 @ 70 isnt too bad at all considering most factory v8 type vehicles turn close to 1800 or so in od with lockup locked right out of the factory, so imo thats pretty ideal at 70... getting outta hand and crazy was the camaro i built with 4.11's and a th 350, no lockup no od and turned an engine wearing 3500rpm all day long @65mph lol
    Everything built in the past 20-30 years is geared too tall in high gear, except maybe driving downhill with a tailwind. When I bought my 2012 Titan new off the lot I picked a 3.36 geared truck over a 2.94 geared truck and still feel its getting 3.73s and a mechanical locker soon. Locked up, in OD and gutless is not my idea of a fuel mileage booster. With the Titan I can drop back into 4th at 80 mph and get within .2 mpg of the same conditions in OD and have lots of power to spare running 2,800 @ 80 mph.
    Last edited by Fast355; 08-14-2013 at 08:20 AM.

  2. #47
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    I'd have to agree here, I had 3.07's in my caddy at first (donor truck had 3.07 in the 12 bolt, as all the power i'm making on a 62 year old rear end that was built for 142 horses sounded like trouble time to me, and just TRY to find a ring and pinion for a '51 caddy... HA!) and then switched to 3.73... I saw little change in MPG (more MPG in city driving with the 3.73 (seeing I didn't have to stab it all the time to move at all), about the same to 65 MPH on the highway, but then over 65, with the 3.73's I'm just rev'ing too high and MPG starts to drop off; i.e. 84 MPH = 3800 RPM; YIKES!). I do love the idea of a hot SBC with a man trans... But for me, the amount of surgery required for a 3rd pedal out weighs my lust for some good ole clutch dumping. Plus My hot rod 4x4 jeep is a 5-speed manual with a 340 HP 287ci straight six (lunati cam'd as well, and the sound a straight six makes at 6300 RPM is just AWESOME) and I can light my 35" tires in 1-3 gears, in 4wd; let alone 2wd... Also, there is something just not quite right about a caddy with a clutch pedal... Oh, thanks for the tip on AE I added 10% to TPS and MAP AE, she loved it, more playing with that tonight... And I still have PE off, as I'm still in fear of hooking up my knock sensor with this huge of a cam. This fall I'm planning to swap out my TH400 for a bowtie overdrive stage III 200-4R, is I can't get the 700-R4 to fit my x-frame without massive re-working of the frame (note to all that need to know it, 200-4R as the same size as a TH400, that can be a life saver). A lower first and a .68 OD, that way I'm not abusing my motor at 84 MPH and top speed should be near 200 (in a car orginally built to only go 75 MPH... that should be plenty). Also no more off the shelf torque converters for me... I'm going to pony up for one built for my motor/RPM range/car/gearing. The caddy is a tad portly for what most high stall TC are built for.
    Last edited by 51caddyman; 08-15-2013 at 12:08 AM.

  3. #48
    Electronic Ignition!
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    Wow! I guess I haven't been getting updates like I thought I was. This has blown up since the last time I checked. I appreciate all of the input you guys have tossed in. After the first 2 pages I had really started to second guess the cam, heads, and intake swap. My parts list was nearing 1500.00 before I even started to figure in my time, labor, and tuning. I noticed summit has complete long block in the 300-375hp range anywhere from 2000-3500 dollar range. Considering I dont know the history or actual mileage of the "rebuilt" engine in my truck, I'm thinking the complete long block may be a better option.

  4. #49
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    Quote Originally Posted by kyotey1693 View Post
    Wow! I guess I haven't been getting updates like I thought I was. This has blown up since the last time I checked. I appreciate all of the input you guys have tossed in. After the first 2 pages I had really started to second guess the cam, heads, and intake swap. My parts list was nearing 1500.00 before I even started to figure in my time, labor, and tuning. I noticed summit has complete long block in the 300-375hp range anywhere from 2000-3500 dollar range. Considering I dont know the history or actual mileage of the "rebuilt" engine in my truck, I'm thinking the complete long block may be a better option.
    The easiest way to get to that 375+ hp range is a crate L31 + LT4 Hotcam kit. It is a very GM efi friendly cam in that it still makes a solid vacuum signal of around 15 in/hg @ 700 rpm unloaded. When car craft had one on the engine dyno under a 650 cfm quick fuel carb and performer rpm vortec with 1 5/8 primary long tubes and dual 2.5" exhaust they made 401 hp and 428 ft/lbs.

  5. #50
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    [QUOTE=Fast355;27080]Everything built in the past 20-30 years is geared too tall in high gear, except maybe driving downhill with a tailwind. QUOTE]
    I agree, a perect example is the 89 Caprice I drove, 2.42 or 2.56 gears, 26" tires, with the 200r4(0.67:1 OD) 305 TBI. It was a stock combination, and required me to pull her down into 3rd gear to maintain speed on the highway when encountering hills.

    I got into an internet arguement with a guy that has a STOCK 2.56:1 gears/700r4 combination in his 88 Caprice, that my recommendation to stick with 3.42 or higher gearing with 27" or taller gears with an OD trans didnt make sense. He said "my Caprice came stock with 2.56:1 gears and the 700r4 and it doesnt lug, I guess GM doesnt know how to build a vehicle correctly."

    I told him he was ignorant if he thinks that GM's builds cant be improved upon by using aftermarket combinations.
    People wonder why they burn out the 700r4's when forcing their heavy vehicles to cruise at 1300rpm.

    peace
    Hog

  6. #51
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    Also, you have to keep the timeframe in perspective, 1988-1989, US car makers were feeling pressure to improve "stated" MPG, so putting a numerically low rear end in, would give those EPA MPG tests much better results. The cost of course being the lifespan of the tranmission, being constantly subjected to less then ideal mechanical advantage, the MPG goes up (on flat testing, like the old MPG test) and the life of the trans goes down. Nothing like a quick stop gap fix. Now that we build our cars for a lifetime, not just until the next model year comes out, we have a far more vested interest in making our parts combos work (as we want them) and last. Remember GM was on the hook for only 3 years/30,000 miles, and then it was yours to fix.

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