143 Blueprint Cam Install

[L78steve]

I have the 143 Crane made cam and it doesn't run worth a darn with the manifolds and the correct dual exhaust .But it sounds good .I need to try headers and a twin muffler set up and see what happens .

[Chevy454]

[ QUOTE ]
I have the 143 Crane made cam and it doesn't run worth a darn with the manifolds and the correct dual exhaust .But it sounds good .I need to try headers and a twin muffler set up and see what happens .

[/ QUOTE ]
I don't wanna sound like a *douche*, but I'll say there's a good chance it ain't the manifolds/exhaust that's hurting the performance...even if it's the original 2.5" exhaust [actually <2" in spots] it'll still let a BBC do it's thing.

[JLerum]

[ QUOTE ]
I have the 143 Crane made cam and it doesn't run worth a darn with the manifolds and the correct dual exhaust .But it sounds good .I need to try headers and a twin muffler set up and see what happens .

[/ QUOTE ]

We have seen this camshaft work very well at the drag strip with decent exhaust. I agree with Rob, it's not the camshaft that is holding you up. If it is then you are very light on the compression. 396/375 motors have made 450 on the dyno with that camshaft.

More camshafts and lifters on the way to those who have ordered. Rob will PM you if its coming to your door.

Jim

[L78steve]

I still think its the exhaust .The car has great torque until the revs increase then it just holds back .Its at the paint shop now,when I get it back I will do some more looking .

[Chevy454]

[ QUOTE ]
I still think its the exhaust .The car has great torque until the revs increase then it just holds back .Its at the paint shop now,when I get it back I will do some more looking .

[/ QUOTE ]
Just as a point of reference, our Y-Camaro put down ~370hp to the wheels through the original manifolds & chambered exhaust, on a 10:1 *bone stock* L72 build...went mid-high 12s @ 108 at a 3700-3800 race weight on Polyglass, running pump gas. With a little more compression, the car now runs high-11s @ 117+, through the same original exhaust manifolds , and a Pypes 2.5" transverese muffler...both engines would easily rev to 7k+. Terry Pennington's Camaro runs high 10s @ 130+ through the exact same exhaust manifolds in the F.A.S.T. class...

One problem I've seen before exhaust-wise is, the flapper in the passenger side down pipe get stuck shut & cause some problems. Any idea where your timing/jetting are?

[larry_csa]

Valve springs
Larry

[L78steve]

Valve springs are originals but were checked .Timing is at 36 total,jetting is 70 primary and stock secondarys on a 4557 carb.The engine has 15,000 miles not rebuilt .My next move will be to set it at TDC and check the mark on the balancer to see if it has moved .I get no spark knock with pump premium and 11:1 comp .

[Keith Tedford]

If you plan on running this car, get rid of those stock valve springs. They either (A) broke and dropped a valve, or (B) couldn't keep up with the cam allowing the valve to free fall shut at high rpm. This eventually pounded the keepers through the retainer allowing a dropped valve again. These are the main reasons that there aren't too many original L78s and L72 out there. We didn't seem to have any problem with the L88 springs in the old days.

[nuch_ss396]

[ QUOTE ]
I have the 143 Crane made cam and it doesn't run worth a darn with the manifolds and the correct dual exhaust .But it sounds good .I need to try headers and a twin muffler set up and see what happens .

[/ QUOTE ]

Steve,

I'd definately replace the original springs ASAP. Take a
trip to the dyno and see what you actually have. Remember
I mentioned that the idle seemed too tame for an L/78.......?

How was the distributor curve setup? There can be a few
issues working together here to rob power. The dyne may
help you identify what they are.

Nuch

[169indy]

Just got Mine Today, PNW.

Thanks for your efforts.

Install in 2010 I hope.

Jim W