Originally Posted By: Lifeguard
Here's another thorough answer. Feel free to shop for the best deals, I just linked to Summit Racing for ease of reference. There might be some alternate parts that are better or cheaper too.

For the HEI, here's my parts list and links assuming you are getting a functional or rebuilt HEI distributor. I recommend the Crane kit because it has the springs and advance you need to do everything. The BWD cap and rotor were higher quality pieces than the stock replacement, and I included the wires and retainer I used (for some reason I can't find the WR1 retainer on Advance Auto anymore). You can probably reuse the coil cover too, and use the stock coil as long as it is good.

Crane Vacuum Advance Kit 99600-1 $35.40 https://www.summitracing.com/parts/crn-99600-1

Fel-Pro distributor base gasket 12665 $0.97 https://www.summitracing.com/parts/fel-12665

BWD HEI distributor cap L6 C198 $34.99 https://shop.advanceautoparts.com/p/bwd-distributor-cap-c198/18200052-P?searchTerm=bwd+c198

BWD coil cap cover C198A $8.19 https://shop.advanceautoparts.com/p/bwd-distributor-cap-cover-c198a/20170298-P?searchTerm=bwd+c198

BWD HEI rotor D157 $13.99 https://shop.advanceautoparts.com/p/bwd-distributor-rotor-d157/18200115-P?searchTerm=bwd+d157

BWD plug wire retainer ring WR1 $3.99 https://www.oreillyauto.com/detail/bwd-3...7/chevrolet/p30

Denso 8mm ignition wire set 671-6020 $39.99 https://shop.advanceautoparts.com/p/dens...=denso+671-6020

Spectre Performance spark plug wire sep 4601 $5.99 https://www.summitracing.com/parts/spe-4601



For the intake and exhaust swap, here's a list of all the major and minor parts you will need to put a 390cfm Holley on an Offy intake mounted with the primaries toward the passenger side. Keep your manifold bolts, but you will need to either use washers with the aftermarket parts, or grind down some of the surfaces to make the factory hold-down pieces seat property.

Offenhauser single quad intake manifold w/ linkage 5416 $309.97 https://www.summitracing.com/parts/ofy-5416

Fel-Pro manifold gasket set MS9786 $9.99 https://www.summitracing.com/parts/fel-ms9786

Holley 4160 390cfm 4bbl carb 0-8007 $488.95 https://www.summitracing.com/parts/hly-0-8007

Holley throttle cable bracket 20-88 $27.25 https://www.summitracing.com/parts/hly-20-88

Holley inline fuel filter 152-523 $13.22 https://www.summitracing.com/parts/hly-162-523

Spectre Performance throttle return spring bracket 4708 $6.99 https://www.summitracing.com/parts/spe-4708

Moroso 0.5” carb spacer 64945 $42.97 https://www.summitracing.com/parts/mor-64945

Moroso carb studs 37961 $14.99 https://www.summitracing.com/parts/mor-37961

Trans-Dapt 3” air filter stud 2174 $1.97 https://www.summitracing.com/parts/trd-2174

Proform 10”x2” air cleaner 66802 $19.97 https://www.summitracing.com/parts/pro-66802

Summit valve cover breather SUM-G3418 $3.97 https://www.summitracing.com/parts/sum-g3418

Langdon Stovebolt cast exhaust headers 42-0070 $277 http://www.langdonsstovebolt.com/store/#!/Stovebolt-Cast-Exhaust-Headers-for-GM194-230-250-292-engines/p/1395980/category=18665955

Langdon Heat Plate 10-9999 $30 http://www.langdonsstovebolt.com/store/#!/Heat-Plate-for-GM194-230-250-292-Inlet-Manifold/p/1222036/category=18665977&forcescroll=true

pair of plumbing pipe tees from hardware store, plus additional heater hose to route coolant to heat plate (not sure on size)

two 2.25” to 2” reducer pipes for the Stovebolts (or is it 2.5" to 2", the Langdon website says 2.25"?)

For the exhaust, you can put on a dual 2" exhaust with dual mufflers or glass packs and keep the six cylinder whoop-whoop exhaust note. If you want to settle the exhaust sound down, then add a crossover pipe or run them through a single transverse muffler in the stock location between the axle and fuel tank. An alternative is to run the dual 2" pipes back to a Y-pipe, then a single 2.5" exhaust and muffler from there to the tailpipe.



For vacuum components, you are going to have to delete the EGR valve and replace its tee to it from the vacuum line. You are also removing the EFE valve and vacuum lines, plugging the sensor whole in the engine block, as this system is replaced by the coolant heat from the heater core running to the Langdon plate on the Offy. I am assuming that you are going the cheap route and replacing the ducted THERMAC air cleaner with a simple open element, and eliminating that vacuum line (if not, then you have to find a 4bbl unit along with a bolt on stove pipe and duct route, but probably keeping the factory breather vent filter in the assembly).

You'll want to keep the PCV and EVAP canister so that you don't smell up the garage with fuel vapor. But the fuel bowl vent line valve will need to be capped as the Holley has open fuel bowl vents. The thermal valve on the water neck will only open vacuum to the EVAP during highway cruising conditions; but not during warmup, idle, or under load. If you have power brakes, you'll need a fitting for the Offy manifold to connect that line. Photobucket will not let me imbed pictures in postings anymore, so here's a direct link to my diagram for vacuum layout on the Holley:

http://i1109.photobucket.com/albums/h434/Lifeguard2005/emission-hose-diagram_zpsux6ry15k.png

http://i1109.photobucket.com/albums/h434/Lifeguard2005/Holley_zpsbwxjpkba.png


WOW!!! Thank you!! Thats what I call being very helpful!

I had no idea those langdon split manifolds were so cheap. Under 300 bucks!! I also had no idea they still sold the Offy intake, and Holley for our adaption process! This is all good news. I can buy a part at a time!

Your information is absolutely appreciated. I feel really at home not like an outsider wanting to keep my 6 in my car! I would truly be happy picking up about 50-75 hp. Looks like that may be possible.