383 Vortec/TBI Build Thread

[Daveo91Burb]

Yeah, there was lots of discussion on my cam choice earlier in the thread. I know it's not the perfect cam for a 383, but I'm using the 1.6 rockers to at least get a little more lift. And this motor is not going to be a high revving speed demon, just want it to have a bit more low end grunt. Throttle body I'm using (46mm) and injectors will also be a limiting factor.

 

[4WDKC]

Yeah, there was lots of discussion on my cam choice earlier in the thread. I know it's not the perfect cam for a 383, but I'm using the 1.6 rockers to at least get a little more lift. And this motor is not going to be a high revving speed demon, just want it to have a bit more low end grunt. Throttle body I'm using (46mm) and injectors will also be a limiting factor.

the stock LT4 cam is was just a 315 hp cam so its not a screamer but would be a nice compliment for a 383, you can usually find them descent priced.

 

[Daveo91Burb]

Yeah I took a look at the specs and it would definitely be better on duration. Lift would be better too but if I kept the 1.6 ratio rockers I would be better off changing springs (see MikeB's post above). LSA is actually tighter on the L31 cam tho. Definitely something to consider for the future but probably won't happen at this stage. I added that one to my spreadsheet I've been keeping of GM cam specs.


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[Daveo91Burb]

Last remaining concern on valve train is pushrod hole clearance. Pushrod not centered with 1.6 rockers. Is this too close?

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[4WDKC]

Looks to close to me.

 

[Honky Kong jr]

Ide open them holes up and put guide plates in but those are press in studs so that won't work.

 

[74 Shortbed]

Easy remedy, put in screw in studs, lol.... And yes that hole needs to be opened up some..

 

[Honky Kong jr]

Easy remedy, put in screw in studs, lol.... And yes that hole needs to be opened up some..

Yes, but that should have been done before they were bolted on. Lol but then again he isn't running high spring pressure either.

 

[Honky Kong jr]

Those push rods make me giggle they are almost cute........almost

 

[74 Shortbed]

Yes, but that should have been done before they were bolted on. Lol but then again he isn't running high spring pressure either.

Yep, should have but no biggie to pull em back off either, lol.. Doubt he'll ever pull one out, but still nice to have guide plates though..

 

[74 Shortbed]

Those push rods make me giggle they are almost cute........almost

LOL...

 

[Daveo91Burb]

I guess I'm missing the joke on my pushrods....

I'm not too worried about lack of screw-in studs and guide plates. My rockers are self-guiding and the springs are stock. Least of my worries right now. Maybe some day....

Too risky to open the holes up with the heads still on? Even with lots of rags placed to catch the cuttings? If I take them off I can reuse the gaskets right? What about the bolts? Vortecs from the factory may have been installed torque-to-yield, but I just used new Fel-Pro bolts and torqued them increments of 20 to 70 fl-lbs.

 

[4WDKC]

I guess I'm missing the joke on my pushrods....

I'm not too worried about lack of screw-in studs and guide plates. My rockers are self-guiding and the springs are stock. Least of my worries right now. Maybe some day....

Too risky to open the holes up with the heads still on? Even with lots of rags placed to catch the cuttings? If I take them off I can reuse the gaskets right? What about the bolts? Vortecs from the factory may have been installed torque-to-yield, but I just used new Fel-Pro bolts and torqued them increments of 20 to 70 fl-lbs.

Believe he is used to thicker push rods for other engines. I wouldnt risk it for the cost of gaskets and bolts your risking your entire engine.

 

[Honky Kong jr]

I guess I'm missing the joke on my pushrods....

I'm not too worried about lack of screw-in studs and guide plates. My rockers are self-guiding and the springs are stock. Least of my worries right now. Maybe some day....

Too risky to open the holes up with the heads still on? Even with lots of rags placed to catch the cuttings? If I take them off I can reuse the gaskets right? What about the bolts? Vortecs from the factory may have been installed torque-to-yield, but I just used new Fel-Pro bolts and torqued them increments of 20 to 70 fl-lbs.

No on the gaskets. And if they are stretch bolt no on reusing them as well. The joke is they are tiny. I'm used to messing with atleast 3/8" push rods and of different lengths. The ones in my engine are 7/16" that's all, it's a big block thing but on later big blocks they used 5/16" ones too.

 

[Daveo91Burb]

Thanks for the replies. No worries on the pushrod joke - figured that's what it was. Yeah they're just vortec stockers. My machinist said they'd be just fine for my build so I went with them.

I drilled out the pushrod holes in the heads - left them on the block when I did it. No offense to anyone that recommended against that. I 100% agree it would have been better to take them off, but I took a calculated risk. Won't know for sure until I fire it up, but I think it turned out OK. Stuffed every hole in lifter gallery (and intake ports) with blue shop towels, packed in a bunch of rags on top, then cardboard to fit, and duct taped the cardboard to the heads. Lots of shop vac and magnet time in between and afterward, lots of cleaning. Magnet comes out clean now. For better or worse.....

Got the entire valve train installed and adjusted tonight, too.

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