Considering Slapping On Heads And Stabbing In A Cam

DorianL

solid fixture here in the forum
Staff member
Greetz All,

My goal is to restore stock performance to my L-46, 1969 Corvette, Coupe. 350HP/370TQ (was it?) and enough vacuum to operate wiper door, headlights and brakes.


Full disclosure... my 1969 Corvette has a turd of an engine. Not a four-bolt. Not numbers matching. 882 heads. It has a new, nondescript GM replacement cam. I think I can hear a bad lifter tick with an automotive stethoscope (which is odd considering the new cam and lifters are new). The valve guides seem a bit worn; at least IMHO based on a vacuum reading and the puffs of blue smoke at start up. I suppose it could be the oil seals…

On the plus side… it has a good idle, stays cool, good compression reading and good oil pressure.

In my pursuit of a head and cam swap feasibility study… I am considering dropping the pan for a closer look.

I do have an oil leak which I think is coming from the rear main seal. Not a huge leak... but just on the edge of annoying. I have a replacement seal and I am debating whether to install it or not.

Either way , this would be an opportunity to examine the bearings, crank and cylinders. I have dropped the pan in the past and found that the cylinders and pistons look ok... No skirt scouring. Crosshatch still in cylinders. It looked clean. For what it’s worth, I did notice that at least one connecting rod nut was a different color. That made me uncomfortable.

If I drop the pan again and the rear cap, I may be opening a can of worms. If I find that the bearings look awful that might bother me even more than living with the oil drip. I might also screw up replacing the oil seal and wind up having to pull the engine… which I certainly don’t want to do till the cruising season is over.


Thoughts ?

MTIADC3
 
I think for the time and money involved and the same amount of work you could wake your 350 quite a bit and still remain way below the radical builds and be just as or more reliable than your engine was in its prime and would put a great big smile on your face when you pressed the pedal
 
first WELCOME BACK!:D

if the goal is simply to build a durable and
close to stock,
but marginally enhanced 350 SBC for daily transportation,

if it was me, Id pull the engine and refresh it on an engine stand to make the whole process, much easier to inspect and rebuild.
theres little sense in my opinion,
in doing the job 1/2 way as its just not that much more effort to do a total re-fresh rebuild
consisting of a disassembly, careful inspection and bearing and rings, lifters, cam , gaskets replacement etc. much easier
I generally use a CRANE 114122 in stock 350 rebuilds
as its an easy 20 more hp over most stock crate 350 sbc and,
it has plenty of vacuum for brakes etc.
and uses stock valve springs.
obviously you can get a good deal more power with better heads and a marginally more aggressive cam, but it might have a mild rumble to the idle sound.
swapping to larger port and larger valve heads with a smaller and more modern design, combustion chamber can easily boost power 30 plus hp even with a very mild cam.
use of higher 1.6:1 ratio roller rockers is an option
https://www.summitracing.com/parts/...MIzrarn7f86AIVHP3jBx3ZpQtWEAAYASAAEgJNtfD_BwE


with a non-skilled buddys help you can easily do the pull, refresh and re-installation in under 1 full two 10 hour day weekend
as Im sure your aware the heads you use to make or break the potential, power curve
heads, headers, and a low restriction exhaust , and a decent intake can in combination go a long way toward boosting the driveability and mid-range power

http://garage.grumpysperformance.com/index.php?threads/sellecting-cylinder-heads.796/


https://www.jegs.com/i/Speedmaster/746/PCE281.2001/10002/-1

https://www.summitracing.com/parts/mll-h8002k?rrec=true

https://www.summitracing.com/parts/bro-1021004





 
Last edited:
Yes .... welcome back my good friend !!! Very happy to see your return !!!

Do you have a budget in mind ? You know you won't be able to resist doing a complete job once you open it up !
 
Dorian I know that you already know the only way to do this is to pull the engine and do a complete rebuild you said that the motor was tired and with that goes worn out if you do it half way you will forever be asking yourself why and if I can remember from the past you are not a butcher when it comes to repairs so get to planning your build and don't cut any corners
 
DorianL you might want to consider a general re-fresh, new rings bearings gaskets etc,
and generally, thats more easily done it the engines on an engine stand rather than with the engine still in the car.

obviously you have many options and ,and its not hard to build in a bit of performance without hurting drive-ability.
it would not be very difficult to boost performance,
and as always a couple hundred people will read the thread, every year or so,
so not all info is directly related to only your particular build,
theres a ton of related info in links and sub links
,
and of course, ask all the questions you might have.
you, or anyone else thinking about an engine refresh in a c3 corvette,
could certainly build something rather street-able with decent vacuum for the power brakes, and stock stall speed auto trans converter,
or build a mild manual transmission combo, or install a manual trans
(generally preferred as its more tolerant of cam selection)
or newer overdrive auto with a higher stall converter, and not hurt long term durability.
be aware the stock hood restricts the intake manifold height change potential choices, and yes an aftermarket BBC hood allows you far more leeway
47976056d1461712338-air-cleaner-options-for-big-block-with-l-88-hood-dsc00858.jpg
194@2x.jpg
c3side3.JPG
index.php

http://garage.grumpysperformance.co...ch-quest-series-similar-350-383-sbc-info.519/

http://garage.grumpysperformance.com/index.php?threads/what-to-look-for-in-a-good-engine-combo.9930/

http://garage.grumpysperformance.com/index.php?threads/the-new-215cc-vortec-heads.266/#post-75012

http://garage.grumpysperformance.com/index.php?threads/matching-parts-and-a-logical-plan.7722/

http://garage.grumpysperformance.co...ily-driver-yet-performance-application.15710/

http://garage.grumpysperformance.co...rebuild-old-dyno-results-new-cam-ideas.15332/

http://garage.grumpysperformance.com/index.php?threads/383-build-for-a-friend.14273/

http://garage.grumpysperformance.com/index.php?threads/plotting-an-l-46-homage.14302/

http://garage.grumpysperformance.com/index.php?threads/355-sbc-bad-combo.13075/

http://garage.grumpysperformance.com/index.php?threads/think-thru-your-goals.10606/#post-73288

http://garage.grumpysperformance.co...y-in-building-a-good-engine.11682/#post-54682

http://garage.grumpysperformance.com/index.php?threads/bits-of-383-info.38/page-2#post-61958

http://garage.grumpysperformance.com/index.php?threads/crate-or-build.11257/#post-50889

http://garage.grumpysperformance.com/index.php?threads/383-information-overload.11137/

http://garage.grumpysperformance.co...solid-515-hp-sbc-build-with-good-parts.11562/

http://garage.grumpysperformance.com/index.php?threads/cam-gear-and-timing-marks-etc.724/#post-93718

http://garage.grumpysperformance.com/index.php?threads/cam-gear-and-timing-marks-etc.724/#post-93718
 
Last edited:
Hey Gang ! How yall been doing :cool:

I hope all is well in these really strange times :eek:

Hmmm... as lot of good feedback here.

For now... I need to drive and enjoy the car for the season. That is why I was thinking of just doing the rear seal, examining and gauging the "rebuilability". It does seem good at first glance.

In my age I became wiser :rolleyes: and retire my cars for the winter when I do the big jobs. Last year I rebuilt the entire front suspension. This year, I did the rear. In fact I just replaced the broken steel spring with a new composite spring yesterday.

Vansteel.jpeg

I will eventually be pulling the engine - refresh seems to be the most cost effective way.

We will start another thread on that. (My plan will be to match or slightly improve on what this car was supposed to have as stock grunt 350HP/370TQ but have all the vacuum accessories operating properly. I also have a T5 trans waiting in the wings o_O)

Right now I don't want to blow my "enjoying season" :D but I do have a leak and... I am thinking I can plug the rear cap plus get a peak under there and replace the seal. Is there any risk to pulling the rear cap ? And screwing up the rear seal job? The rear seal not coming out or sliding in... I would HATE to miss the "enjoying season" particularly as my wife actually enjoys (you heard me right, ENJOYS :confused:) riding in the Corvette.
 
Since the engine is not the original, you should obtain a 96-2000 Chevy/GMC truck Vortec engine. Then you would benefit from a factory roller cam setup, 1-piece rear main seal, and Vortec heads with raised rails and centerbolt hold-downs. The only differences will be that this block is not fully machined for the mechanical fuel pump, and your flexplate will be different due to the 1-pc rear main seal. It will bolt right in. Cruise the car this summer while you are building your replacement engine. Then do a swap over the winter. You will be miles ahead this way.
 
Since the engine is not the original, you should obtain a 96-2000 Chevy/GMC truck Vortec engine. Then you would benefit from a factory roller cam setup, 1-piece rear main seal, and Vortec heads with raised rails and centerbolt hold-downs. The only differences will be that this block is not fully machined for the mechanical fuel pump, and your flexplate will be different due to the 1-pc rear main seal. It will bolt right in. Cruise the car this summer while you are building your replacement engine. Then do a swap over the winter. You will be miles ahead this way.

I have been thinking about that I as well. I think it may be possible to find one of this over here. I am running a sump-type fuel pump to run my EFI. It is fed by the mechanical pump. It works well, but it clutters the engine bay. I will eventually move to and in-tank fuel pump.
 
Since the engine is not the original, you should obtain a 96-2000 Chevy/GMC truck Vortec engine. Then you would benefit from a factory roller cam setup, 1-piece rear main seal, and Vortec heads with raised rails and centerbolt hold-downs. The only differences will be that this block is not fully machined for the mechanical fuel pump, and your flexplate will be different due to the 1-pc rear main seal. It will bolt right in. Cruise the car this summer while you are building your replacement engine. Then do a swap over the winter. You will be miles ahead this way.

How prophetic you were... found one !
 
Dorian do your research on installing the fuel pump in the tank it may not work because that year had engine mounted mechanical fuel pump but I'm sure there are other options and as you know there is a lot of knowledge on here
 
even if you go to another block do yourself a favor and go with a set of aftermarket aluminum heads with the money you save from the roller cam setup
 
Back
Top