97loudcut Posted January 29, 2007 Report Share Posted January 29, 2007 Well I bought the 3400 upper and lower intake manifolds from BrianP. I was just curious. I don't plan on doing the LIM until it gets warmer out, I have more people, and I have more time. I was just wondering, since it is such an easy job, would I see any benifit from just temporarily swaping JUST the UIM? Quote Link to comment Share on other sites More sharing options...
birdman Posted January 29, 2007 Report Share Posted January 29, 2007 from what ive heard theres not much to gain from doing the upper and lower swap but id still go for it. Quote Link to comment Share on other sites More sharing options...
jeremy Posted January 29, 2007 Report Share Posted January 29, 2007 from what ive heard theres not much to gain from doing the upper and lower swap but id still go for it. swapping both would certainly be worth the install... Quote Link to comment Share on other sites More sharing options...
Brian P Posted January 29, 2007 Report Share Posted January 29, 2007 Can't be done. The 3400 style ports are that much larger, they will overlap the lower ports by a long shot. Plus the bolts wouldn't line up if it were to work. FWIW the '00+ 3100, using manifolds with the same sized ports, gained 15 hp and 10 lb ft of torque. Nothing to scoff at. Quote Link to comment Share on other sites More sharing options...
BIGBULS Posted January 29, 2007 Report Share Posted January 29, 2007 Don't forget the slightly larger intake ports and valves and redesigned rear exhaust manifold........the intakes were MOST of the power gain, but not ALL of it Quote Link to comment Share on other sites More sharing options...
Brian P Posted January 29, 2007 Report Share Posted January 29, 2007 the rear exhaust manifold was the same from '97 on, unless I missed something on that. At least on w-bodies, where I got my #'s from. And yes the intake valve changed from 1.72" to 1.76". Quote Link to comment Share on other sites More sharing options...
Crazy K Posted January 30, 2007 Report Share Posted January 30, 2007 As the proud owner of one of these 3400 topend swapped motor, now with working EGR thanks to a simple self made adapter, the ass-dyno says it's got plenty of power. It's hard to tell, but when it downshifts at highway speed I think it pulls better. And I was getting 29mpg at 75 mph! I've been missing good gas mileage. my solution for the exhaust flow is to upgrade the exhust system. hows about a 3.4 system from behind the cat back? p.s. $30 for yet another 3400 van intake with roller rockers and everything. The best part is the van had one 3400 head, and one 3100 head! Quote Link to comment Share on other sites More sharing options...
GP1138 Posted January 30, 2007 Report Share Posted January 30, 2007 Matt, let me know whenever you decide to do this. Ken and I will try to help somehow. It's not a bad mod, I love the power I have on the highway. That's not to say that it's more than a few horsepower, but I definitely feel more pull at higher RPM's than before. Quote Link to comment Share on other sites More sharing options...
97loudcut Posted January 30, 2007 Author Report Share Posted January 30, 2007 I was thinking, ince it warms up to have a mini meet somewhere and get this done. I know Tony would be down. To make it easier on you guys I wll come down by you. LMK when is a good time to do it.. Im open for anything. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted January 30, 2007 Report Share Posted January 30, 2007 No way- I wouldn't let you drive your car to do something to the engine. What if something happens and we can't finish it? You'd be stuck! Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted January 31, 2007 Report Share Posted January 31, 2007 My house....? Ehh, I doubt my garage will be clear. Quote Link to comment Share on other sites More sharing options...
slick Posted January 31, 2007 Report Share Posted January 31, 2007 Matt, you know I'm game for the swap. It's not gonna take long with 3 guys working on it. Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted February 2, 2007 Report Share Posted February 2, 2007 Matt, you know I'm game for the swap. It's not gonna take long with 3 guys working on it. x2. With Chris, Me, and You..we could knock it out in 3 hours....Best Buy install bay...what? Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted February 2, 2007 Report Share Posted February 2, 2007 If it's sometime after this month and I have my license back, I'll be up to help out. Quote Link to comment Share on other sites More sharing options...
5speedz34 Posted February 2, 2007 Report Share Posted February 2, 2007 If it's sometime after this month and I have my license back, I'll be up to help out. How big of an if is the license thing? Seriously I would love to meet... Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted February 2, 2007 Report Share Posted February 2, 2007 It's a 50/50 chance I'll get it back. Quote Link to comment Share on other sites More sharing options...
GP1138 Posted February 2, 2007 Report Share Posted February 2, 2007 I'll do my best to come. Quote Link to comment Share on other sites More sharing options...
jeremy Posted February 2, 2007 Report Share Posted February 2, 2007 I'll supervise, just like I did when "we" swapped Chris' wiring harness Quote Link to comment Share on other sites More sharing options...
97loudcut Posted February 2, 2007 Author Report Share Posted February 2, 2007 Yeah we should pan this.. I can't wait! Quote Link to comment Share on other sites More sharing options...
Crazy K Posted February 3, 2007 Report Share Posted February 3, 2007 I've gotten good enough to do the entire swap as a 4 hour job... parts and warm day permitting. Here's my quick synopsis: This was done on my 95 3100, My 95's 3100 turns out to have been a crate motor installed relatively recently in the life of my car... but whoever stuck it in the car over-torqued everything. Car ran poorly due to a combination of mis-sealed gaskets and damaged sensors. I picked up parts from two damaged 3400 motors at a local yard. Here's what I got, all came from two 97 chevy venture vans... Yes, I am prepping for a second swap, but both vans were missing parts. Injectors: appear the same as the 3100s so I discarded them. Later 3400 use a different fuel injector, which I have read elsewhere should not be used since they would run too rich in my swap. alternator reinforcement brackets for the 3400 are different. not the big one bolted to the side of the block. These are the small black ones that reinforce and prevent vibration of the alternator. There are two, and the bridge from the back of the alternator to the intakes. upper intake. Mine is stamped 3400 and has a horizontal EGR. lower intake. bigger bores is a plus! throttle body/butterfly. the 3400's is bigger, but the throttle linkages have changed. however the throttle shafts can be swapped. remove the TPS, and you will discover a 'slip washer' on the shaft. (shut up john!)that must be pried off. Remove the torx bolts from the butterfly and pull the disc out and it all comes apart. install the 3100's shaft in the 3400 throttle body with the 3400's butterfly disc. done. the 3100 throttle bracket has one hole changed from the 3400. You will notice this upon reassembly. Drill a hole through the bracket at the new position or else you will have a wiggling throttle bracket... maybe uneven throttle too. 3400 engine cover used in vans add a nice touch. 3400 pvc tube is different, it only matters if you want to install the engine cover. 3400 van map sensor bracket is different, it only matters if you want to install the engine cover, which has the provision to hold the rear of the van plastic cover. oil cap 'extender' locks down the front of the plastic cover(same used on 3800 series IIs?) push rods are the same length as mine, with the different length for intake and exhaust, valve covers are the same, if your 3100 has plastic valve covers they can be swapped up. The roller rockers went right on, my 3100's heads were pre-slotted. However, my 94 CS's 3100 is not, and the pedestals are much smaller. a suggestion of cutting notches will not work. the 94, when done, must have the lower intake clearanced to accept the older rockers, or have the heads changed. buy the Fel-pro permaseal 3400 intake gasket! you must drill a hole in both heads for one dowel pin that GM relocated on the intake gaskets. (easy) use a torque wrench to get everything right. I made my own EGR adapter using a drill press and a piece of 1/8" aluminum stock. it's too ghetto but I'll fab up a better one later. I got the 3400 van EGR tube but was unable to separate my 3100's egr tube, so it is ghetto for now. I plan to get a 96-97 3100 EGR tube to see if is the same Quote Link to comment Share on other sites More sharing options...
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