Id suggest reading up on the 1984-1996 C4 corvettes and getting several auto trader and corvette trader magazines
if you want to perk up a cross fire corvette porting the intake and a cam swap helps
but replacing a stock restrictive intake to a converted SY1 or SMOKEY RAM INTAKE is a HUGE improvement in air flow!
Van Mattiza from Edelbrock indicated the SY1 was made in the late '70s and early '80. The castings were either broken or lost and would not be produced again.
SY-1 Intake Article Nov 2002 Car Craft had a resto article on an SY-1 intake they picked up at a swap meet. While they were playing with it they dropped it on an engine on a dyno. Results: "we found prestigious midrange torque, making 466 lb-ft @ 4600 rpm and 468 hp at 6000 with a Holley 750 compared to 443 lb-ft at 4600 and 486 hp at 6300 with the same carb atop a modern Edelbrock Victor single-plane intake." Article does not say how the small block engine was cammed or what heads, but the SY-1 produced very respectable numbers.
http://web.archive.org/web/200603220017 ... tallation/
read these threads
viewtopic.php?f=32&t=1148&p=5322&hilit=crossfire#p5322
viewtopic.php?f=32&t=2796&p=7243#p7243
http://jobyteknik.homeip.net/corvette/2002-11_offy_installation/
viewtopic.php?f=86&t=1397
this is the largest cam ID suggest using in a stock cross fire with auto trans , its good for a 25-30hp gain and works with all stock components and gearing
this is the largest cam ID suggest using in a stock cross fire with manual trans , its good for a 30-35hp gain and works with all stock components but it really works much better with 3.54:1-3.73:1 rear gearing and a larger fuel pump and adjustable f/p regulator
ok basics
keep in mind the concept of a chain is only as strong as it WEAKEST LINK
the stock heads flow less than 200cfm, the stock intake flows less than 200cfm and the stock cam is designed to max out at about 5000rpm, so you need to change all three components to get a noticeable improvement.
keep in mind the cars geared , stock to run in the 1200rpm-5000rpm power band.
if you want to keep the basic cross fire intake design the renegade intakes designed as a well designed improved flow intake, the OFFENHAUSER crossram intake can be modified for even better flow rates but its a good deal more work,
youll want heads that maximize the low and mid rpm flow potential so look for heads in the 180-200cc port size that flow at least 245-250 cfm at .500 lift
obviously a roller cam will provide more air flow than a similar duration flat tappet cam, but if you go much above 206 duration on an automatic trans you'll want a high stall converter or above about 212 duration on a cam for a manual trans or a auto trans you need to change rear gears to get the full benefit. and this is not the limit of what can be done to increase performance potential, a longer duration cam with more lift can be used to increase the average rpm and power band
but keep in mind all component changes tend to require further matching changes in compression,rear gear ratio, converter stall speed and air and fuel supply , header config. etc.
yes you can rapidly find that what you started out to build will require a great many more changes to be a well matched functioning combo than you originally thought might be required, and while you can increase power levels significantly , your finished project may have little in common with the original engine configuration.
https://www.corvettemods.com/C3-C4-...ke-Manifold--Crossfire-Injection_p_14318.html
http://garage.grumpysperformance.com/index.php?threads/ported-crossfire-383.10240/#post-41065
http://garage.grumpysperformance.com/index.php?threads/got-a-cross-fire-corvette.640/#post-25767
http://forum.grumpysperformance.com/viewtopic.php?f=32&t=2796&p=7243#p7243
viewtopic.php?f=52&t=181
viewtopic.php?f=52&t=5078
viewtopic.php?f=52&t=3802
viewtopic.php?f=56&t=495