LT1 cam similarities with Fuelly?

[Justin N.]

Dear Members,
I saw this 58 fuelly early Thursday at the Golden Gate meet. What drew me to it was the exhaust rumble! Are the Fuelly's cams solid lifters? Can I expect similar sounding exhaust from a 67 327/3oohp with Camelhump heads, #490 aluminum intake, 3810 carb, and LT1 cam kit from GM? It's a rear exhaust car and I was looking at the Allen's 'off-road' kit. Thanks much!
Justin #41362

[Duke W.]

Re: LT1 cam similarities with Fuelly?

C1s sound different than C2s even though the '62-'63 SHP/FI 327s have the same Duntov cam as the C1 "high horse" FIs and the 283/270. There was also a "low horse" 283 FI that used the mild base engine cam, but they are rare. What you probaby heard was a 283/290 with the Duntov mechanical lifter cam.

The reasons are several fold.

1. C1s with the Duntov cam do not have a vacuum advance, which means blowdown pressure at idle is higher when the exhaust valve opens. Installing the LT-1 cam on a C2 with a vacuum advance will somewhat mitigate this difference since the LT-1 cam has a very early opening exhaust valve - about 20 degrees earlier than the Duntov cam.

2. The two generations have completely different exhaust system configurations. The larger C2 pipes create a somewhat lower fundemental frequency and the muffler designs are different. Also, FI C2s have no exhaust crossover, either via a heat riser passsage or an external crossover, so the two sides are completely isolated with uneven out of phase pulses due to the uneven firing order on each bank. Crossovers result in a higher and even fundamental frequency since both sides "see" a cylinder firing every 90 degrees and both sides are in phase. The existance or lack of any kind of crossover will dramatically alter the sound we perceive on a cruciform crankshaft V-8.

3. I don't have a firm handle on what C1 engines had external crossovers versus those that didn't, and it may have even varied with year for the same basic engines. Maybe the C1 guys can fill us in.

I have never heard C2 that sounded as good as the best C1s, and it's a combination of all the above reasons why they sound different. I still remember the time I first heard a '58 283/290 FI when I was about 12 years old, and I was totally hooked.

I'm always amazed how many guys choose a cam primarily on "how it sounds at idle". The best strategy is to select a cam the makes the best torque bandwidth. If you want it to sound "mean" cruising through the Bob's Big Boy parking lot, disconnect the vacuum advance.

Duke

[Craig S.]

Re: LT1 cam similarities with Fuelly?

Justin - the LT1 cam is solid lifter, and the fuelies were too. There are some timing differences, but you should get a similar sound. Your compression with 327/300 pistons may not be set the same as original 327/350 specs and the 490 is for the 327/350, but it should be a good setup nonetheless.......Craig

[Michael H.]

Re: LT1 cam similarities with Fuelly?

Justin,

If you have what is basically a 300 HP motor but want a different cam that sounds good, you may want to consider the 65-67 3863151 350 HP cam. This is a hydraulic lifter cam so there would be no frequent lifter adjustment necessary and it sounds as good or better than the LT-1 cam at idle. It's been a favorite of many for years, and, it's a correct part for a 67.

The 57-63 097 cam had a sound all it's own and no other GM cam ever sounded quite the same.

[Justin N.]

Cam Sounds!

Thanks for the help guys! I'm running Keith Black flat tops and I've already purchased the LT1 cam kit, so that's the one I'm going to use. The 58 literally spun me around when I heard the exhaust note. The only other car to sound that good was this 69 L89. A bit odd with the automatic tranny, but still was raucous. I was about twenty feet away, next to Kevin's 67, and you could smell the VP racing fuel coming off the side exhaust, Yummy! I was just hoping for a little bit of lope to it, as I haven't heard a LT1 idle before.
Justin

[Warren F.]

Re: Cam Sounds!

That's no L-89!

[Chas Kingston]

Re: Cam Sounds!

Lookd more like L-88 to me.

Ol' Geezer

[Duke W.]

Re: Cam Sounds!

That looks like Jon Stachan's '69 L-88 THM.

Duke

[Patrick H.]

Re: Cam Sounds!

Beautiful suffix sticker on that thing, too.

Patrick

[Dick W.]

Re: Cam Sounds!

Tis Jon's car at the Berkley Regional. From the sunshine, I would say the photo was made Friday sometime. Very nice car.

[Clem Z.]

Re: LT1 cam similarities with Fuelly?

FI cars had no exhaust crossover in the intake manifold like a carburated car so the exhaust will sound different. i think some FI had a exhaust crossover built into the heads pipes to quiet the exhaust

[Jon S.]

Re: Cam Sounds!

Yep - That was my car. It was a great meet, and no environmental protesters despite running the car several times!

And yes - there was a perfect suffix sticker on the valve cover. Not only did I get no deduct, I'm pretty sure I got a bonus point or two.. :-)

[Patrick H.]

Re: Cam Sounds!

If Dick judged your car, then you probably did.

Patrick