Many thanks for posting these sort of 2.8, 3.1, 3.5, and 3.5 GM V6 videos. They came in handy when I put a new set of heads and gaskets on my 2002 Oldsmobile Silhouette. Just to confirm, it is also impossible to make any of the early 2.8, or 3.1 upper intakes mate to the 3.5 LX9 engines, and work with an Oldsmobile Intrigue 65mm throttle body? The 3500 swap instructions at Milzy Motorsports say a 3100 upper intake might work with the 3.5, but was curious to see how. Found a Oldsmobile Intrigue 65mm throttle body from the junkyard the other day for when the right project comes along.
The 65mm TB will not work easily on a 2.8/3.1 plenum, there is not enough material to open it up that large. The TB will work on a 3100 plenum, and small port plenum with some modifications but I would recommend just upgrading to the large port top end first! Happy to hear that the videos have been helping others! Thank you!
It seems strange that they LOWERED the ports on the 3x00 heads as compared to the 2.8/3.1 heads. MOST manufacturers seem to RAISE the ports on the better heads.
The intakes don't show the mismatch very well compared to the heads, but they did get raised on the 3400 heads about 1/2" or so. I will try to show it better maybe in a short or in another video!
A 2000+ 3100sfi will be a direct swap for a 3400 sfi. If you're asking about 3.4sfi (1993-95 camaro/firebird), swapping with a 3100 that will not work as they are different.
But the intake plenum and exhaust ports are the same across the 2.8 and 3.1, right? My 2.8 just kicked the bucket and I'm contemplating switching to a 3.1 longitudinal from a Camaro or similar, but I can't find a clear answer about whether the ancillaries are all compatible or not - seems like maybe everything except the water pump would be ok?
Is it a FWD vehicle that your are working on? The RWD blocks are different than the FWD blocks. Cylinder heads, intakes, starter location are the main differences.
@@illililililillli the 3.4 block is a LQ1 which is a quad cam V6. It don't use pushrods. and the 3.1 Cavalier 3.1 MFI is the same as the W-Body 3.1 MFI.....
@@RobertOrtega You're right lol I guess that wasn't the vehicle I used the pushrods from. I know I used stock pushrods from a early 90s GM. I thought it was a 91 3.1
@@modeverything1 I've kinda got skin in the game with this topic. Got a 1994 Camaro with the 3.4 v6. Been wanting to do the 3500 swap but not sure if it is going to be worth it. I'd like to be around as close to 250 lb ft. of torque as possible. Any ideas?
Also been thinking of buying a pullout LT1 350 with complete wiring harness and transmission and calling it good. I'm not tech savvy enough for an LS style swap.
Many thanks for posting these sort of 2.8, 3.1, 3.5, and 3.5 GM V6 videos. They came in handy when I put a new set of heads and gaskets on my 2002 Oldsmobile Silhouette. Just to confirm, it is also impossible to make any of the early 2.8, or 3.1 upper intakes mate to the 3.5 LX9 engines, and work with an Oldsmobile Intrigue 65mm throttle body? The 3500 swap instructions at Milzy Motorsports say a 3100 upper intake might work with the 3.5, but was curious to see how. Found a Oldsmobile Intrigue 65mm throttle body from the junkyard the other day for when the right project comes along.
I. too found an LX5 throttle body at the local salvage yard on one of my recent trips. One day, I hope to grab an LX9 top end to swap onto my LA1.
The 65mm TB will not work easily on a 2.8/3.1 plenum, there is not enough material to open it up that large.
The TB will work on a 3100 plenum, and small port plenum with some modifications but I would recommend just upgrading to the large port top end first!
Happy to hear that the videos have been helping others! Thank you!
COOL! Thanks Man... Answers 1of those questions. "Ain't They the same family of Blocks, so shouldn't They fit one another?"
what about the super charger from a grand prix on to a 3.1?
It has been done before but with a modified intake plenum and it has to have a hole cut in the hood. Not a "bolt-on"
It seems strange that they LOWERED the ports on the 3x00 heads as compared to the 2.8/3.1 heads. MOST manufacturers seem to RAISE the ports on the better heads.
The intakes don't show the mismatch very well compared to the heads, but they did get raised on the 3400 heads about 1/2" or so. I will try to show it better maybe in a short or in another video!
Do you know if the lower intake from a 3.4SFI could be a direct replacement for the lower intake from a 3.1SFI?
A 2000+ 3100sfi will be a direct swap for a 3400 sfi. If you're asking about 3.4sfi (1993-95 camaro/firebird), swapping with a 3100 that will not work as they are different.
But the intake plenum and exhaust ports are the same across the 2.8 and 3.1, right? My 2.8 just kicked the bucket and I'm contemplating switching to a 3.1 longitudinal from a Camaro or similar, but I can't find a clear answer about whether the ancillaries are all compatible or not - seems like maybe everything except the water pump would be ok?
Is it a FWD vehicle that your are working on? The RWD blocks are different than the FWD blocks. Cylinder heads, intakes, starter location are the main differences.
@@modeverything1 nope, it's all RWD.
@MistahMatzah RWD to RWD should be a fairly straightforward swap
If I were to get some nice new 3400 heads for my 2.8, will that work?!🫣
You would need the 3400 intakes as well. If you are in southern Ontario, let me know, I have some extra 3400 heads/intakes!
Hey i just got a question about the intake gasket for the 3.1 MPFI, where would i find a set?
The last set I got was from rockauto.com but any parts store should be able to order them for you!
I wonder if one could simply swap the engines. Seems the easier route.
Yes, you can swap the complete engines. It's not much more work than replacing the engine, and it is a great improvement!
Wait what about the heads upper and lower
The 31/3400 heads will bolt on to the 2.8/3.1 blocks. Just have to make sure you use the matching intakes for the heads!
Would the 3400 fit on my 97 cutless supreme 3100??
Some have used the 3400 intakes on the small port 3100s like yours but you will see better results using 3400 heads and intakes.
the only way is to use the heads with custom pushrods.
1991 Cavalier 3.1 pushrods are the perfect size for using 3x00 heads on 3.4 block 😏
@@illililililillli the 3.4 block is a LQ1 which is a quad cam V6. It don't use pushrods. and the 3.1 Cavalier 3.1 MFI is the same as the W-Body 3.1 MFI.....
@@RobertOrtega You're right lol I guess that wasn't the vehicle I used the pushrods from. I know I used stock pushrods from a early 90s GM. I thought it was a 91 3.1
@@RobertOrtega the lq1 isn't the only 3.4, there's also the l32 in the F body which is probably what Leo was referring to
3400 swap onto an iron head chevy 3.4l v6 is common. People use the better heads though.
Yes, most like to use the 3500 heads when using the stock pistons to help lower the compression for pump gas!
@@modeverything1 I've kinda got skin in the game with this topic. Got a 1994 Camaro with the 3.4 v6. Been wanting to do the 3500 swap but not sure if it is going to be worth it. I'd like to be around as close to 250 lb ft. of torque as possible. Any ideas?
Also been thinking of buying a pullout LT1 350 with complete wiring harness and transmission and calling it good. I'm not tech savvy enough for an LS style swap.
If you did 3500 top end on a 3.4 iron head engine, cam and headers you would probably be getting close to 250 ftlbs.
LS swap would not be too bad, lots of information on the web!