3500 head swap

[SE'sarecool2]

OK, here goes nothing... I know the 3500 UIM can be retrofitted on any 3400 with the proper throttle body adapter, DIS mount fabrication, MAP sensor swap/modification, TB bracket modification, etc. Will the 3500 heads bolt on as well? What changes, if any, would be needed to do this? I've been reading on GMEnthusiast.com that the valves are bigger than previous 60 degree V-6s. The rocker arms are the same ones used on the LS1 V-8... so any aftermarket roller rockers for the LS1 would work without grinding the LIM or the rocker arm. Has anybody else thought of the power increase these two modifications together would provide? Am I crazy for asking this?

[Doubt_Incarnate]

i know one way to find out... get out the band-aids and wrenches and get to work.

you'll have to think about if those valves will fit in the smaller bore.

[SE'sarecool2]

you'll have to think about if those valves will fit in the smaller bore.

all I would have to do is bore the block & get get bigger(3500) pistons

[SappySE107]

They have the same size valves. There will be more on this once phil gets his 3500 top end swap done this week. I doubt they are LS1 rocker arms. Maybe the same bolt size but i dunno about the rest of it matching up.

[SE'sarecool2]

Here's the link and a quote from it and the guy who wrote it

http://www.gmenthusiast.com/gallery/laautoshow2005/powertrain2.php

Indeed, cylinder bore diameter wasn’t the only chapter taken from the GM small-block performance playbook. The valve spring rocker arms are the same parts used in the LS1. And when it comes to the cylinder heads, the 3.5L V-6’s valves are nearly LS1-sized, too, with 47.5-mm intake valves and 38.7-mm exhaust valves.

Contact:
Nick Richards
GM Powertrain Communications
Phone: (24 857-0163
E-mail: nick.richards@gm.com

[SappySE107]

You can put 3500 valves into a 3400 head without doing any work. Im not sure what 3500 he is talking about but its not the one found in the malibu or G6.

[SE'sarecool2]

'06 Impala & Monte Carlo

[SappySE107]

Yeah, thats a different setup and will not bolt onto the older blocks. That 3500 is a 3900 bore with a 2.8 stroke. Thats why its got the larger valves as well.

[onefastV6]

There are two different 3500 engines. The 3500 and the 3500 VVT which apparently use different heads.

I will be installing the 3500 heads from a 2004 Malibu (same as the current G6) These heads use the same rockers as the 03+ 3400 engines, same cams, lifters and a few other similarities. I will let everyone know how the install goes and what my thoughts are.

As for the 3500 VVT heads I am not sure if they will fit or not there are alot of factors that will have to be determined before they are determined a direct fit for the 3400. As far as I know, no one has pictures of a torn down 3500 VVT head.

[SE'sarecool2]

Darn! Oh well, thanks for clearing that up anyway. Let me know when you get a kit together for the 3500 plenum swap - I want one; or if its easier, a parts list with part #s. Thanks!
-Joe

[rx191]

i have a set of 2006 non vvt 3500 heads and everything should work as long as you have the lower intake and rockers. the exaust will bolt right up from a 3400 and the 3400 fuel rails will fit the manifold, i think there is a water fiiting that is in a different spot but i haven't looked at teh stuff in a while. other than that they are a bolt on affair. i just haven't had time to do it myself yet.

[AaronGTR]

As for the 3500 VVT heads I am not sure if they will fit or not there are alot of factors that will have to be determined before they are determined a direct fit for the 3400. As far as I know, no one has pictures of a torn down 3500 VVT head.

Check out sappy's post above yours. He says the 3500vvt heads have a 3900 bore. In that case they would not fit a 3400 block since the 3900 bores are larger and they're also offset. You'd have to use non-vvt 3500 heads, in which case I'm not sure there would be any benefit since they're "almost" the same as 3400 heads.

[onefastV6]

As for the 3500 VVT heads I am not sure if they will fit or not there are alot of factors that will have to be determined before they are determined a direct fit for the 3400. As far as I know, no one has pictures of a torn down 3500 VVT head.

Check out sappy's post above yours. He says the 3500vvt heads have a 3900 bore. In that case they would not fit a 3400 block since the 3900 bores are larger and they're also offset. You'd have to use non-vvt 3500 heads, in which case I'm not sure there would be any benefit since they're "almost" the same as 3400 heads.

I will let you know as I am starting the tear down here in about an hour to swap to the 3500 heads. I am going to say there is a benefit, just compare the 3400 and 3500 heads side by side.

My mods will soon include complete 3500 top end, TOG headers, 65mm throttle body, Borla catback, and tuning.

[Syn]

i am guessing your going to be using a 4.3 t/b correct?

[xtremesunfire]

so you guys are saying that 3500 heads would work on a 3400 block? and also about the 3500 valves where can I get them at?