Hmm, wonder how much work it is for JUST a head swap- might be worth it for 20 HP. Unless there is a better aftermarket choice for heads? I assume that's the only part giving more power in the Series III that's Camaro applicable?

 

I have read about the 20 hp from the SIII heads on this site before. I am not sure where that number comes from. The SIII valves are .020" larger. Normally you do not see a 10% HP gain from a .020" increase in valve size. Infact I wold not expect much differents in the Dyno test at all unless the valves where the bottle neck. I just looked up the 2008 Grand Prix and it is listed at 200 HP. My guess the is the .020" helps a little on the lower end but not much on max HP.

Could be a worth while upgrade if your doing head gaskets anyway and you already have headers and you gasket matched the intake.

 

didnt they use a different cam and lifters with the heads to help get the hp?

 

The cam, rods, pistons an crank are identical from SII and SIII, the only difference is the heads. Not only is the intake valve larger but they improved the flow characteristics of the heads to give them the bump in power.

To the OP, Look in the main page of the V6 section and you will see a thread there about what engine can be used for a replacement. I spent a few hours researching what cars had what engine and what engine is compatable to create that thread. It also tells you what parts need to be used off your old engine and what parts are universal between FWD and Fbody engines.

Stay away from GTP, or SSEi engines as the supercharger engines are not compatable with the Fbody without alot of mods to the car and engine. Also the Cam, Crank, Rods, heads, injectors and... well everything except the block is different.

Massey

 

That is the thing, the SIII motor is not rated for any more HP than the SII motor. I would guess the work they did was for low end torque. You can feel it but it has no effect on Max HP out put.

 

Hmm, interesting discussion, here's the specs from GM circa 2004 Grand Prix:

PONTIAC | GRAND PRIX | SPECIFICATIONS | ENGINES

Engine, 3.8L 3800 Series III V6 SFI with Electronic Throttle Control (200 HP [149.2 kW] @ 5200 rpm, 230 lb-ft [310.5 N-m] @ 4000rpm)

Engine, 3.8L 3800 Series III Supercharged V6 SFI with Electronic Throttle Control (260 HP [149.2 kW] @ 5200 rpm, 280 lb-ft [310.5 N-m] @ 4000rpm)

 

I just wish u could fit the hole gtp motor that's would be a very fun motor to have

 

GM actually did a 4th Gen Firebird with the SC3800 in it using off the shelf parts they were able to make it work. The car never went into production because of the difficulty getting everything to work properly together. and fit where maintenance could still be preformed with out any major work.

Massey

 

I'm still leaning towards a 350 from tbi to Carb swap and trying to do a standard conversion on it

 

Did you do the research on this site? its been done by two people. The first one spent 5K and the second one spent 11K. Like you neither guy had any idea what they where getting into. You have to make parts. No one sells them, well you can buy the K frame needed for like $600 but everything else needs to be fabricated.

We are talking rewiring power windows all new gages, custom made gage cluster. Converting a car is a great learning project but you are going to spend big money and in the end you will have a car worth less than the stock V6. Oh and both project took 100's of hours of one and the one is still not done. You better have a full shop and a car lift will make the process much easier. If you are really going to do at least get a V8 that will out run a V6. The 305 have weak bottom ends and strech rods really easy. They where designed to be a light small blocks for fuel mileage. I have install a lot of crank kits in the 305 even in the 140 HP version on cars with less than 50,000 miles on them. They do not get stronger with age.

https://camaroforums.com/forum/93-02...4-5-7-a-45720/

https://camaroforums.com/forum/93-02...ictures-68220/

Converting a V6 to a V8 with a doner car (the easy way)
https://camaroforums.com/forum/93-02...-thread-68658/