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Old 12-14-2015, 05:35 AM
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Günther-C3 Günther-C3 is offline
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Default Searching for cam for 427ci BigBlock

Hello!
I have a 69 Corvette with 427/390hp BigBlock and want to change the cam. I want to have low end torque as much as I can get and idle well below 1000 rpm (NOT rough idle wanted).
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What do you think about this cam? Other advices?

Regards, Günther
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Old 12-14-2015, 06:36 AM
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Twin_Turbo Twin_Turbo is offline
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link doesn't work.

Need more specs, what kind of heads, compression, intake. exhaust...etc etc.

Might want to consider a roller cam upgrade, a little more costly but gains will be significant.

For a flat tappet, a adv 282/294 @50 222ish 236ish 112seperation would work for a 1900-5500 range in a 427. you will noit want a smaller cam that lives from idle to 4K and redlines a little over. the car will feel like kicking a dead mule up in the RPM range.
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Old 12-14-2015, 10:16 AM
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Günther-C3 Günther-C3 is offline
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Hello!
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Everything on the engine is stock. I don´t want go with roller because the rest of the engine is stock. If I would build it up from scratch, I would go with a roller.

Regards, Günther
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Old 12-14-2015, 02:03 PM
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JPhil JPhil is offline
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I ran a flat tappet XE262 with 114* LSA in my first small block engine with 9.75:1 compression and AFR heads. It had real good lower end torque and ran strong up through the RPMs. Nice smooth purring idle.

In my second rebuild, all I changed was going to a XE268 with 110* LSA. It had noticeably less lower end torque. Came on stronger up toward 3000 RPM, but (comparatively) felt like a pooch before that. A little lumpy idle.

I preferred the XE262 for street use. By 4500-5000 RPM, I could feel it was running out of poop, but I very rarely ever go that high.

In my new 10.4:1 CR 383" stroker, I'm running a Lunati single pattern roller cam of 274* advertised, 218* @ .050" and 112* LSA. It is very strong in the lower end and up as far as I want to go.

With your stock heads, a dual pattern cam is probably best.

I don't know what difference the big block vs. small block has on cam performance, but Lunati told me you want to add a bit of duration with increased stroke. I debated going the next step up to a 224* @ .050", but I'm just as glad I didn't. I have a real flat torque curve, with 400+ lb/ft from 2500 to 5250 RPM.
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Old 04-27-2016, 04:14 AM
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Quote:
Originally Posted by Günther-C3 View Post
Hello!
I have a 69 Corvette with 427/390hp BigBlock and want to change the cam. I want to have low end torque as much as I can get and idle well below 1000 rpm (NOT rough idle wanted).

Regards, Günther
For my L88 clone 427 engine in my 69 Coupe, I used the cam specs for the L88. I'm sure I bought the real L88 cam from GM performance parts. It had one thing you posted that you don't want..low torque at low RPM's. For the other thing you wanted was an idle at stock engine rpms. I had a 50 pound flywheel so it would idle at normal RPMs.

The L88 engine power at higher tach values was just explosive. However, with the stock cam, getting the car rolling from a city street stoplight was painful...I had to slip the clutch to get it rolling due to the low torque from the engine at off idle. I bought a 5 speed, a Doug Nash 5 speed, due to the car's 3.08:1 diff. This was a perfect tranny...no problems getting going in city traffic off a traffic light. If I remember correctly, the Doug Nash 5 speed with a 3.08:1 rear end was pretty much the same as as a stock tranny with a 4.56 to 1 rear end in first gear. No problem getting rolling.

The Doug Nash 5 speed is now marketed as a Richmond Gear 5 speed. It looks the same, however my understanding is that Richmond cheapened the tranny by lowering the torque ratings of the engine. For a stock 427/454, the Richmond is just fine.

Since I wanted to run much more HP than a stock BB, I decided to switch to a Tremac 5 speed. It's rated at about 1000 ft-pounds if I remember correctly. However, you can't reasonably use a Tremac with a 3.08:1 rear end. To go with a Tremac 5 speed, I had to change the diff from a 3:08.1 to a 3.73:1 differential. I have the same Tremac 5 speed in my 68 SB. The 68 has a 3.73:1 rear end. The 68 will, like it's sister, in Tremac 5th gear cruise at 70 mph with about 2000 rpms on the tach. However, at low engine RPMs taking off from a stop light, the Tremac speed has very much adequate torque in first gear.
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