Appreciation - A Grumpy Follower

Bubbagum

Member
Just want to introduce myself and say how much I appreciate my fellow hobbyist and professionals. When I was a kid, I had lots of friends now scattered
everywhere that could help me with my car projects as I helped them. I felt good being around them and they were fun. Lately on another corvette forum we lost a member. He was a great contributor to the car community, a professional corvette builder, knowledgeable and never hesitated to pass that knowledge down to anyone. That's what it all about to me helping out when you can.
I have always used the internet from the beginning as a source for my hobby. Almost every time I punch in question specs and how To's Grumpy's garage was there. That's said something. Weather it a buget rebuild or something more intense, I'm glad now I belong to this forum.
 

Bubbagum

Member
I’m going out of my mind with measurements.
 

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Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
THANKS FOR THE POSTED PHOTOS
you certainly have a project on your hands
what are your plans on the engine rebuild?
 

Bubbagum

Member
THANKS FOR THE POSTED PHOTOS
you certainly have a project on your hands
what are your plans on the engine rebuild?
Hi Grumpy
Nothing fancy. She was running good when I took it apart. I took the body off to fix a lot of things debated on just painting the engine and reinstall you no how that goes. Bird cage is mint. Frame mounts needed a little work. Frame over all is in great shape. But it is a crossfire that acutely grew on me. Renegades are hard to come by. Heads are the leased desirable but there in good shape no cracks. I do know the block is going to be stock. Heads? Intake? Cam looking for roller idears. I can’t believe the cam and lifters that came out was in very good condition. I plan on using it for trips to the North Carolina. If it was a 67 vette with a 396 it would be different. I inherited it from my younger brother. He had cancer and I didn’t want to let it go. So this one is going to be a fun cruiser. I have a bucket list. 69 Cuda notch keep coming to mind. Hey I appreciate any ideas for a light engine build. I don’t think port matching the intake on my spare time is going to do much.
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
if you can afford to get into a rebuild, you really would benefit from upgraded cylinder heads,
power increases are almost always directly related to increased efficiency in increased air flow and fuel flow rates,
you can't burn fuel without that increase air flow into and burnt exhaust gases flowing out of the exhaust, the stock GM crossfire intake was designed for the 305 displacement SBC to maximize lower and mid rpm torque, thats the rpm band where 70% plus of the time the cars engine is used to maximize fuel economy performance was not the main concern, upgrading the heads and intake, air flow rates has huge benefits in potential power,
the cross fire intake design maximizes the inertial ram effect the longer runner length has to increase cylinder fill rate efficiency

increasing the port cross sectional area in the heads and intake runner boosts potential power.
yeah it will take you a few days but read through this thread.. as it contains a good deal of related useful info





this hobby's never cheap, but you can get amazing results from a carefully thought out upgrade/ change in parts:like:
as both the stock cross fire heads and intake are very VERY restrictive.
every change has a compromise required,
but matching parts and thinking through the changes leads to far fewer issues and much better power.
the following suggestion would provide a street performance upgrade ,
allowing easy daily driving, yet a big boost in performance over almost all of the power band.
you would be amazed at for a daily driver but certainly not a race engine
(you'll be amazed at the results of the upgrade linked below should you decide to go that route)

yeah, there will be some minor custom fitting/linkage fabrication etc.

and tuning required as the stock throttle body's and fuel delivery will need to be upgraded to match the power increase
but the heads and intake and cam together should easily exceed 80-90 hp PLUS or more, a better fuel pump and marginally boosted fuel pressure aids the power curve. obviously retuning will be required to maximize results.
I've done similar builds and you'll be impressed with the results should you choose to follow the upgrade parts suggested

if you have a low restriction exhaust.
raising the compression and keeping the cam timing mild, yet with a vastly improved flow rate's from heads and intake has a huge potential boost in mid rpm and upper rpm power.

doubling the stock hp and measurably improving the tq is certainly within reach if your wallet allows you to go for the upgrades

Id look for either a renegade or OFFY and a mild hydraulic roller cam, similar to this,
the combo listed should boost power very noticeably
in seat of the pants acceleration, especially if you add a better fuel pump and swap to a 3.54:1-or 3.73:1 rear differential gear ratio.
the offy far out flows the renegade, intake but you'll need the better heads, and cam swap, roller rockers etc.
to take advantage of the much improved flow rates, and the rear gear ratio change would transform the drive characteristics very noticeably with the parts upgrade


obviously ask questions about what plug angle clears your headers/exhaust manifolds, but Id get 195cc -200cc port heads
and do the math to get the correct combustion chamber size to get between 9:1-9.25:1 cpr Id look for 1.6:1 ratio steel roller rockers
that fit the stud size the heads come with, and use a mild roller cam.


or

ofy-5903.jpg


ofy-5893.jpg


http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/
OFFY BELOW
ofy11.jpg


ofy22.jpg


Intakeoffy.jpg



its the links and sub links that contain the vast majority of the useful info
and if you want to dive in way over your head a 383 config would further boost your power an easy 50 plus added additional hp.
over the potential gains already suggested.










 
Last edited:

Bubbagum

Member
OMG. Thank you so much. That is a lot of information. What a response. This is going to be a good read,possibly hours of research.
if you can afford to get into a rebuild, you really would benefit from upgraded cylinder heads,
power increases are almost always directly related to increased efficiency in increased air flow and fuel flow rates,
you can't burn fuel without that increase air flow into and burnt exhaust gases flowing out of the exhaust, the stock GM crossfire intake was designed for the 305 displacement SBC to maximize lower and mid rpm torque, thats the rpm band where 70% plus of the time the cars engine is used to maximize fuel economy performance was not the main concern, upgrading the heads and intake, air flow rates has huge benefits in potential power,
the cross fire intake design maximizes the inertial ram effect the longer runner length has to increase cylinder fill rate efficiency

increasing the port cross sectional area in the heads and intake runner boosts potential power.
yeah it will take you a few days but read through this thread.. as it contains a good deal of related useful info





this hobby's never cheap, but you can get amazing results from a carefully thought out upgrade/ change in parts:like:
as both the stock cross fire heads and intake are very VERY restrictive.
every change has a compromise required,
but matching parts and thinking through the changes leads to far fewer issues and much better power.
the following suggestion would provide a street performance upgrade ,
allowing easy daily driving, yet a big boost in performance over almost all of the power band.
you would be amazed at for a daily driver but certainly not a race engine
(you'll be amazed at the results of the upgrade linked below should you decide to go that route)

yeah, there will be some minor custom fitting/linkage fabrication etc.

and tuning required as the stock throttle body's and fuel delivery will need to be upgraded to match the power increase
but the heads and intake and cam together should easily exceed 80-90 hp PLUS or more, a better fuel pump and marginally boosted fuel pressure aids the power curve. obviously retuning will be required to maximize results.
I've done similar builds and you'll be impressed with the results should you choose to follow the upgrade parts suggested

if you have a low restriction exhaust.
raising the compression and keeping the cam timing mild, yet with a vastly improved flow rate's from heads and intake has a huge potential boost in mid rpm and upper rpm power.

doubling the stock hp and measurably improving the tq is certainly within reach if your wallet allows you to go for the upgrades

Id look for either a renegade or OFFY and a mild hydraulic roller cam, similar to this,
the combo listed should boost power very noticeably
in seat of the pants acceleration, especially if you add a better fuel pump and swap to a 3.54:1-or 3.73:1 rear differential gear ratio.
the offy far out flows the renegade, intake but you'll need the better heads, and cam swap, roller rockers etc.
to take advantage of the much improved flow rates, and the rear gear ratio change would transform the drive characteristics very noticeably with the parts upgrade


obviously ask questions about what plug angle clears your headers/exhaust manifolds, but Id get 195cc -200cc port heads
and do the math to get the correct combustion chamber size to get between 9:1-9.25:1 cpr Id look for 1.6:1 ratio steel roller rockers
that fit the stud size the heads come with, and use a mild roller cam.

or
ofy-5903.jpg


ofy-5893.jpg


http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/
OFFY BELOW
ofy11.jpg


ofy22.jpg


Intakeoffy.jpg



its the links and sub links that contain the vast majority of the useful info
and if you want to dive in way over your head a 383 config would further boost your power an easy 50 plus added additional hp.
over the potential gains already suggested.










OMG. This is great. Thank you so much. It must of taken you some time to gather this information. It’s going to take me some time to go over all of it. The offinhauser intake would be a great benefit to the motor. Just saw your reply and haven’t gone threw it yet, but quick question on the offy. Do you make up your own cover or can you for the throttle body’s so it fit under the hood and your shop is in NH?
 
Last edited by a moderator:

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
there are adapters made to convert the carb base mount to allow the throttle bodies to mount on the offy intake
or you can fabricate two rather easily, obviously going with the renegade intake removes the need to do a great deal of fabrication and it will also produce a good deal of that power increase, you want and do so a bit easier obviously as its designed to do that,
while the offy , being a basic dual quad carb intake modified to use on a dual throttle body intake ,with larger runners for race use, has MORE potential peak power and greater potential air flow,
but if your sticking to the mild cam linked in the suggested parts list , that cam selection is designed to both maximize the torque curve and remain easily street drivable, you'll have a hard time taking advantage of that extra air flow rate potential, the offy has,
as even the renegade intake has more potential airflow than the mild cam timing and lift will allow in either intake manifold.
 
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