low buck junk SBC

prairiehotrodder · Post by **prairiehotrodder** » Sat Nov 23, 2019 11:55 am

I have an 80 malibu 4 door that i used last summer to teach my son how to drag race. In the junior street program it runs mid 9's in the 1/8 mile. Cars in this program are limited to 9.0 in the 1/8th. Last summer it had a stock TBI 350 that had a stock iron 4 barrel intake and Q-jet bolted on it. It was fun to drive with a turbo 200 tranny that worked suprisingly well and a 3.42 govloc rearend. I sold that motor a couple weeks ago and am putting another one in. Just basically doing this for the learning experience with my boys. Little to no money to spend on it. I bought a turbo 350 that i'm gonna install for $100 from a friend that looks to have a shift kit. Now for the motor : Another stock TBI 350 out of a 94 chevy pickup. This one is milled and drilled for a factory roller cam but it doesn't actually have one, just the stock flat tappet. I have all the parts to put a stock vortec roller cam in it. Is there any power in doing that ? I would still be using the TBI heads. Also would likely install the stock windage tray thats in a vortec motor.
Anyone know the specs on the TBI cam vs the vortec roller cam ? Thanks

Here is a picture of my son with his Mom who was his co-driver

IMG_2881_0.jpg

dannobee · Post by **dannobee** » Sat Nov 23, 2019 1:05 pm

Do you have the cam retainer plate? Is the 94 block machined for it? Does the cam have the fuel pump lobe? I thought those cams were missing the fuel pump lobe since all of the vortecs had electric fuel pumps. Also, the blocks have the pad for the fuel pump but none of the holes were drilled. Make sure the 94 block has those, too. Lobe lift was 0.285 E and 0.276 I on the 5.7 vortec cam

turbo camino · Post by **turbo camino** » Sat Nov 23, 2019 1:45 pm

I have a '95 truck TBI/swirlport block, came with a flat tappet but all the provisions for the roller. Fuel pump boss is 100% complete and functional, EXCEPT for the front hole used to lock the pushrod during install isn't drilled through. Be aware there are two different bolt spacings for the front retainer plate - 3.62" & 3.294".

The roller cam will definitely make more power than a flat tappet with half its lobes floating around in the bottom of the oil pan.

'96-up L31 roller cam is 191/196 @ .050, 255/266 @ .004, 111 LSA, .412/.423 valve lift. But it has NO fuel pump lobe. There are some B-body LT1-style cams with the same profile but with the pump lobe.

prairiehotrodder · Post by **prairiehotrodder** » Sat Nov 23, 2019 2:00 pm

Since i had a TBI motor in there last summer i already am set up with an electric fuel pump. Thanks for the tip on the cam retainer plate. May have to buy one. Also will any old SBC timing chain bolt on the vortec cam ? Probably requires one with a smaller bolt circle ?
Brian

Post by **FC-Pilot** » Sat Nov 23, 2019 2:28 pm

Yes the bolt circle is different for the factory roller cams. You will need a timing set for the factory roller cams.

I have to say that of the things I have seen on speedtalk in the last few months that pic of your kid and wife is the coolest. Making a difference in a kids life is just awesome.

Paul

econo racer · Post by **econo racer** » Sat Nov 23, 2019 2:58 pm

COOL

I wonder what gain you would get by just bolting on a performer intake?

turbo camino · Post by **turbo camino** » Sat Nov 23, 2019 3:02 pm

Keep in mind you can use any stepped-nose style cam, doesn't matter if it was intended for the late Gen1 or LT1/LT4. Or, any retrofit cam with the old style timing gear + thrust button, and all the rest of the OE lifter parts in the valley.

All factory roller cams are steel and will eat a plain old style distributor gear, use GM# 10456413 if you have a .491 shaft (big cap HEI).

turbo camino · Post by **turbo camino** » Sat Nov 23, 2019 3:14 pm

turbo camino wrote: ↑Sat Nov 23, 2019 1:45 pm'96-up L31 roller cam is 191/196 @ .050, 255/266 @ .004, 111 LSA, .412/.423 valve lift.

Minor correction, I scrolled farther down the txt file and found where I measured actual lobe lift at .276 I / .286 E, .414/.429 w 1.5 rockers.

Post by **GARY C** » Sat Nov 23, 2019 3:46 pm

These 2 links should answer your original cam question as well as the difference in specs between the 2 engines
https://www.gmperformancemotor.com/parts/12703983.html
https://www.gmperformancemotor.com/parts/12681432.html

rebelyell · Post by **rebelyell** » Sat Nov 23, 2019 7:10 pm

GM pn 24502586 "Hot Cam" is popular upgrade I: 218 / E:228 I: .492 / E: .492

as a GM factory steel billet roller, it also needs a melonized dist gear.

Understand OP has electric fuel pump, but hot cam does have a fuel pump eccentric /lobe.

like that family racing thing too! $\:D/$

1980RS · Post by **1980RS** » Sat Nov 23, 2019 9:42 pm

turbo camino wrote: ↑Sat Nov 23, 2019 1:45 pm I have a '95 truck TBI/swirlport block, came with a flat tappet but all the provisions for the roller. Fuel pump boss is 100% complete and functional, EXCEPT for the front hole used to lock the pushrod during install isn't drilled through. Be aware there are two different bolt spacings for the front retainer plate - 3.62" & 3.294".

The roller cam will definitely make more power than a flat tappet with half its lobes floating around in the bottom of the oil pan.

'96-up L31 roller cam is 191/196 @ .050, 255/266 @ .004, 111 LSA, .412/.423 valve lift. But it has NO fuel pump lobe. There are some B-body LT1-style cams with the same profile but with the pump lobe.

The B-body cam is the same as the 96-97 Camaro LT4 cam, next step up was the Hot Cam.

prairiehotrodder · Post by **prairiehotrodder** » Sat Nov 23, 2019 10:33 pm

thanks for your help guys. I managed to scrounge all the parts to get the vortec cam in without buying anything. My cam doesn't have the fuel pump lobe as was mentioned. I wondered about the dist gear. Thanks for the part number ! The stock vortec gear, does it fit on the HEI ? Also hopefully the TBI valve springs will handle the vortec cam.

Funny thing about my wife, she thought that malibu was the ugliest most embarrassing car ever. Then one day at the track she was sitting in the staging lanes and some guy comes up and tells her that he used to have a 4 door malibu and he thought they were the coolest cars ever. Suddenly she likes the car, likes racing, and likes spinning the tires every chance she gets. He did me a big favor.

Brian

dannobee · Post by **dannobee** » Sat Nov 23, 2019 11:57 pm

Vortec heads had beehive springs with smaller retainers. And didn't have valve rotators.

turbo camino · Post by **turbo camino** » Sun Nov 24, 2019 5:34 am

Need to clear up which engine when we say 'Vortec', as the pre-'96 TBI/swirlport was called 'Vortec' too. The '96-up stuff I call L31 to avoid confusion.

The TBI distributor gear won't work as it was the one for the flat tappet cam. The L31 'crab cap' distributors have a smaller shaft than the old-school big cap HEI, I think it's .431" vs .491". It's the right material but wrong shaft size. The # I listed is the crossbreed gear to put the older distributor on the newer steel cams.

turbo camino · Post by **turbo camino** » Sun Nov 24, 2019 5:46 am

1980RS wrote: ↑Sat Nov 23, 2019 9:42 pm The B-body cam is the same as the 96-97 Camaro LT4 cam, next step up was the Hot Cam.

Only the 'baby LT1' L99 used the cam you mention, the other B-body LT1s used the 191/196.

Don Terrill’s Speed-Talk

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