Well being at university you tend to dream about things... like swapping a 3.4L into my car (or another car, depends on job, and summer events)

I have thought about a few things.

1-What are the specs on the stock cam? Because I know it is quite a bit better than the 2.8 Cam I was wondering if the Phase 3 cam from ARI would swap in Computer mod free. Phase 3 cam specs http://www.engine-parts.com/GMV6/28camspecs.html

2-Since it will be a 3.4 swapped in, and they make headers for them will I be able to fit them around the frame, or will I have to mod them to have them fit?

3-Roller Rockers, I believe I would want 1.52 rather than 1.6.
But then I got to thinking about putting 1.52 on the intake and 1.6 on the exhaust to help it breth better, would this work, or would I need computer modifications?

 

I can't answer 1 for ya
2.yes they will have to be modded to fit
3 .go with 1.52 b/c when you nail it (nail the gas) you will hear them hitting on the valve covers ....of course you may not mind that , its up to you but if it was me id go with the 1.52 .You shouldn't need any computer modifications .but dont hold me to it , I could be wrong !

Yeah , I was dreaming at the boneyard the other day when I walked into a warehouse with everything from engines to posi rears .I was drolling all over a 3.4 engine . Swap a girl in the passenger seat to while your at it

 

Girl is already swapped in ...lol, but see that adds weight and makes me slower... I hope she never reads this lol...

 

Stock cam specs for 85-up "HO" 2.8/3.1 MPFI:

Duration @ 0.050" lift
I: 196 degrees
E: 202 degrees

Advertised duration:
I: 238 degrees
E: 256 degrees

Lobe Separation:
108 degrees

Gross lift (after 1.5 rockers):
I: 0.393 inches
E: 0.410 inches


I don't think the computer will be too happy with the low manifold vacuum of the Phase 3 cam. Low manifold vacuum usually indicates a large valve overlap; the computer might not like that.

 

True forgot about that, thanks for the info, I think I will write about that and ask.

 

Get a cam thats computer friendly .

 

hmmm I wonder if a computer friendly one would work . It seems maybe all that new air to the computer could make something off ..I dont know ...Tom , what do you think man ?

 

Once you get the stock running 3.4 in, you'll be so STUNNED, you'll never want to touch it.
IT'll run so smooth, get incredible gas milage, idle like a purring girlfriend
The car will leap over mountains where you're 2.8 struggled.....
Save the extra effort for the new rear tires & new rebuilt tranny you'll need!
Everyone else or anyone else who also swapped in a 3.4, went thru their old tranny.
200 foot pounds of torque and a happy right foot, seem to have a problem co-existing under your hood!
Happy New Year, all!

 

KARL !!! HEY MAN !!! HOW WAS YOUR TRIP ??? I was unable to watch for you on MTV , did you and the car make it on there ?

 

Hi Wayne, send me an email.
Great trip, missed the snow, by days, (that was an 8" one day storm!). Would still be trapped back east!

 

did the trannies just give up the ghost, or would a shift improver help? Need answer before engine swap!

 

I got SOME milage from the tranny I had in the car.
Then, it started to slip on the freeway. I changed fluid & it went good bye. #-4 Clutches burnt up.
NO SHIFT IMPROVER KIT BEATS A GREAT TRANNY REBUILD JOB!!!!!
IF ya got the time, NOW is the time to rebuild the tranny, real solid.
Ask on the tranny side for local shop recomendations.
I have to rebuild a 700R4 shortly. For my S-10 Blazer.
I can't wait to get it from Wisconsin. I hate being patient, so tired of it!
Do what ever youcan, NOW, to make the swap go real smooth.
Rebuild distributor now, it's easy, too.
Check all fuel stuff.
Do anything ya can, now.

 

Thanks Karl,

Those are things I wanted to know, I still didn;t stock specs on the cam so if anybody has them please post.

As far as the 3.4, I ow my University 5870 and I only have 4800, *sigh* so a 3.4 conversion looks like its a long ways off. But I still continue to read your 3.4 Boogie over quite often, everytime picking up on new details... hoping that soon I will be able to do this swap.

 

The cam you install in the 2.8 is basically the stock 3.4 cam.
I was so pleased to have linear poewr band, not peaky power band like in the 2.8 MPFI engine.

 

I'm not sure.. if the 2030 cam is close to the stock 3.4 cam, and the 2030 cam's meant for the 2.8 computer, than a 3.4 cam should work with the 2.8 computer. With a MAF system, I think the computer would handle the 3.4 perfectly. But I'm not sure about a 90-92 SD system. The computer might handle the cam but not the engine? Would vacuum #s be different between a 2.8 and 3.4?

 

FWIW, the Comp Cams 1.6 roller tip rockers fit under the stock covers. If you think about it the ratio shouldn't affect whether they clear or not. If the same cam is used, the pushrod still travels just up as far as it did before whereas the valve end goes down and away from the cover. True roller rockers are often higher so you have to check clearance.

I used these on an '86 carbed 2.8 because the cam was so anemic. It's hard to say but I think it helped with midrange torque (not much high end even at the best of times). The car didn't drive much different.

From my V8 experience I can say that putting the same cam in a larger engine tends to smooth it out and lower the rev range. eg., the W-31 cam for an Olds 350 gives about 10-12" of vacuum at idle from it's advertized 300 degree intake duration. The same cam was also used in the 455 and it ended up being much more tame than in the 350.

Regarding emissions and whether the computer will work with a larger displacement, I would bet that you'd have far less trouble going up than going down. The engine is just an air pump and as long as the cam is not so radical as to spit mixture back into the intake it just moves more air per cycle and the computer should compensate.

Cheers,

Duane