Oh BK has a 383 - that is a whole different ball game.
I'm talking "stock" 300 hp 327 here.
The Vortec's is as high dollar as I intend to go.
Will have to see if my old heads (soft valve seats) will last a few more years (yeah I know everyone [on here] says seat recession is an old wive's tale - we'll see !).

 

wait, I'm getting confused. your not the OP..? he has a rebuilt 350, not a 327.....

 

One of the things I have learned in the process of doing my own build is that the size of heads and pistons are not neccesarly what they are advertised to be.
My 64cc SHP Dart heads showed up and when I cc'd them they were 67cc not 64cc as advertised. Called dart and they said yes that is within spec. 3cc's could drop your CR by 3 tenth's of a point on your CR.
Then there is the thickness of the head gasket was that calculated in properly?
Finally the pistons that were supposed to be around 15cc's were 17cc's.
Also learned that pistons with an advertised Compression height of 1.56 in a stock built motor may show up with something less than that, so then the piston is farther down the bore at TDC further reducing your CR.
Any one of these things would have a negative effect on your CR and added up could have a large cumulative affect all conspiring to lower your power output and final CR.
Your Cam is pretty short so that cam would probably even serve a 8.5 CR just fine, just at a lower power level.
If everything else checks out, carb,timing, sufficient intake air, decent exhaust flow then I might suspect cam was not timed in properly, or CR is low, or just too small of a cam.
Check your cranking pressure with a compression gauge and compare it to the amount you get from this calculator to see if it's at least close. You'll need to know your intake valve closing angle.
I ran it with you at 1000 feet and an intake closing of 56* and came up with 158 psi for your CR of 9.6.

http://www.wallaceracing.com/dynamic-cr.php

 

79 you have the heaviest vette ever made. Trying to shorten the cam duration did not make a real torque engine out of a 350 you found that out. You don't want any rpms so what is your new plan ?

You would have been worlds ahead putting the L/82 crank to the side buying a $200.00 scat cast steel crank in 3.75 stroke but its to late for that now.

More gearing in the rear or another manual trans could get the heavy car rolling a lot better. Other then that your going to have to make up your mind to get power with a 350 it has to be at least a mid range power engine.

Figure out how much lift you can get out of the vortec head then put the duration of the L/82 cam back in it with a more modern cam design.

 

You guys do realize this thread is almost 5 years old, right?

 

this is exactly why I decided before hand, if I was gonna go through the hassle and work of removing my stock 350 from my heavy 78, whatever went back in, was gonna be enough power that I would't be disappointed and feel like I wasted my time and money.

 

damn it I got sucked into a 5 year old thread. and no i didn't realize it until now.

 

okay Duh looked through the posts somemore found it : EX262 , which Matt way back said dyno'd pretty much like the GM 476 cam.

Back then Matt commented that the EX262 was a pretty cam lobe wear aggressive cam.

Sounds like I just have to keep my ears open for a 476 take out cam and lifter "package"

 

It is a fast ramp. I use 20w50 VR1. Maybe that helps? A stock 962 cam was tested by GM to last 100,000 mi. XE262 can't be expected to last as long.
With the oil filter bypass plugged, a cam failure usually does not require a rebuild since the shavings get trapped in the filter. So i don't worry about it.
.
I hope the OP chimes in. He has had just enough time to fix it
the 476 cam has really long ramps for long life. 320/324/112.5
That could be the cause of the OP's complaint. Soggy low end, this does not show up on the dyno. So, i would not buy the 476. BUT, someone that drives 25,000/year might love it for its long life.

 

lol, no

 

What rear gears ?

 

I researched the vortec cylinder heads. What kept me from choosing them was I wanted OEM appearing underhood, I really like the stock ram air set up (1980 L48) and don't want to mess with an aftermarket air cleaner, drop base, etc. And, I wanted to boost performance AND reuse all of the parts that I have (my headers, performer intake, q-jet carb, ram air, etc.).

I also considered a crate/replacement engine. But, most have vortec style heads. And, I don't have the tools or support to swap engines.

I opted to give my DART 72cc heads a refreshing by purchasing a retro rolling cam kit with pieces for the cylinder heas from Comp with comparable duration to my Crane Energizer 272H10 hyd flat tapet grind. What made me very happy is it is all made for my Gen 1 parts combo; I get the roller valve train and get to give it a nice freshening across the board on the top end. When I am finished, all I will have removed are the cam/lifters and valve train pieces. And, I'll have all-new top end gaskets/seals and much improved performance.

 

That's too funny man. DOH!!!

 

Doh!!!

 

Knowing full well this is a 5 year old thread, looks like you could run a Q-Jet with vortecs with the Edelbrock 2116.



Ah, right... it is 1/4" higher on the A measurement and 3/4" higher on the B. D'OH!

 

Yep on my '59 that difference in manifold height is critical, and I have even lowered the motor, the Edelbrock intake is too tall !
The only Q'jet intake I could possibly use is the PP intake

 

I know this is going to sound harsh, but really being direct is the only way I can figure to say this (and it's echoing what was said above).

You put heads on a motor that:flow more, and get the mixture swirling (better mixture and combustion). Then you choke the motor with a smaller cam. I'm not sure why you didn't expect what you've built.

Timing, I don't think, is your issue - but you might be able to get some back with timing. Most motors are happy at 36* total. What did you do for your weights in your distributor? What springs in the distributor? Is your vacuum advance working? Especially in your case, the lightest springs available would help. What vacuum pressure moves the advance? Guessing, again, 16 psi would be the right setting.

Still, for maximum efficiency and power that cam needs to change - the XE262 recommended above is a good one.

By way of comparison - I have a 350 truck bottom end in my Corvette (mid-70s low compression); Vortec heads; Comp Thumpr cam; 4 speed; 3.08 gears; holley 780 (now FAST Efi); DUI distributor (set at what I recommended above - except 10# on the vacuum); MSD ignition; hooker side pipes with reverse flow mufflers. I light the tires at any time in gears 1-3. Prior to the 4 speed, I had a turbo 350 with a 2400 stall - it'd light at any point in 1st, and if you didn't roll into the throttle while it was in 2nd, it'd light the tires.

 

Wow Buick that sounds pretty impressive.

I have since changed my mind about changing the cam.
It is VERY tempting but then I thought of all the work to do it on a C1 (and I have a couple of BB 67's I need to get going on and cash in on before this whole scene starts dying just like the people are LOL)
I think I will just see if there are any 1.6 rail rockers to retrofit the Vortec heads and leave it at that.

My stock cam and lifters are nicely run in (after 35 years) so shouldn't have any issues.

My car is also a road trip car - mileage and reliability are somewhat important

Which ST-10 are you running 2.88 or 2.64 or ?

 

3.44/2.28/1.46/1.0

 

Holey toot !
No wonder you can break the tires loose at will with the 3.08's

I was going to run the 3.42 ST-10 (have a couple) but don't need or want such a low overall 1st gear so will be looking for a 2.88 box.
Have a 2.64 just to try out first when the 3.08's go in.