Quick engine help needed.... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

n737nc · 06-27-2004, 08:41 AM

I am in the process of swaping heads, cam, intake this weekend on my 350.

The old intake had a vacume port to use for the modulator valve for the tranny, the new one does not.

Is it OK to run this vacume line to the carb? If so, whick port should I run it to?

Thanks,
Nick

jay6891 · 06-27-2004, 09:10 AM

You can run it to your carb. Should be the full manifold vacuum port. Just like the old one.

ChevLoRay · 06-27-2004, 09:45 AM

He's right. I had to get a tee to route vacuum to both the brake booster and the modulator.

I even replaced my modulator with the smallest one that was available, because I no longer have the kick-down linkage with the carb/intake change. I had my transmission valve body modified for crisper shifts, and the shop put that small modulator in at the same time. It is black, in case color coding matters.

It still doesn't kick down like it would with the linkage to operate the switch, but it is decent. Up shifts into drive (accelerating onto freeway ramps) occur at about 52MPH. I havent' tried to see where it is on a Low-2nd upshift.

I have the Lokar linkage and mount to install to operate the switch, I just haven't procrastinated enough.

06-27-2004, 08:41 AM	#1
n737nc Registered User Join Date: Jun 2004 Location: Dallas, Tx Posts: 207	Quick engine help needed.... I am in the process of swaping heads, cam, intake this weekend on my 350. The old intake had a vacume port to use for the modulator valve for the tranny, the new one does not. Is it OK to run this vacume line to the carb? If so, whick port should I run it to? Thanks, Nick

06-27-2004, 09:10 AM	#2
jay6891 Car Knocker Join Date: May 2001 Location: jefferson,arkansas Posts: 664	You can run it to your carb. Should be the full manifold vacuum port. Just like the old one. __________________ 68 c-10,91 sportside bed,350 .030 over,4 bolt,10-1 comp,2.05 intake/1.94 exhaust,1.6 Harland Sharp roller rockers,edelbrock rpm cam and intake w/750 carb, 700r4, 3.73 gears,Jacabbs Electronic Igntion w/Accel HEI distributer and super coil. ZR-1 roll pan, filled tailights. Blazer tank. Hidden hitch. 2 1/2" Flowmaster 40's. Parts bought but not installed>> ford 9" posi with disc. CCP front and rear lowering kit 4/5. Cab corners,foor boards,rockers, cab braces, Phatom grill, Painless wiring kit.

06-27-2004, 09:45 AM	#3
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	He's right. I had to get a tee to route vacuum to both the brake booster and the modulator. I even replaced my modulator with the smallest one that was available, because I no longer have the kick-down linkage with the carb/intake change. I had my transmission valve body modified for crisper shifts, and the shop put that small modulator in at the same time. It is black, in case color coding matters. It still doesn't kick down like it would with the linkage to operate the switch, but it is decent. Up shifts into drive (accelerating onto freeway ramps) occur at about 52MPH. I havent' tried to see where it is on a Low-2nd upshift. I have the Lokar linkage and mount to install to operate the switch, I just haven't procrastinated enough. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.



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