ATTN: CaddyRob (DOHC)

[FieroBUZZ]

I read your post at PFF and thought I would chime in here without starting a flame war. I'm not trying to discourage you but give more info.

Just three items:
Your 84 have no provision for a v-6 so you will be drill some new mount holes no matter what goes in.  Should not be too large a problem.

The DOHC is in no way cheaper than a 4.9 swap, either to buy install or maintain.  Read this and be warned.
http://www.angelfire.com/ca2/34Performance/dohc.html Don't get me wrong, I love a twin cam.  I had a Fiat spider twin cam for years.  The problem I see is a junk yard motor of this complexity should be redone before use.  At the very least the timing belts and pulleys changed.  If you don't feel up to this, read big bucks as special tools may be needed.

Last, the 4:10 is not going to cut it.  The reason the 2.8 guys use it is that it provides that off the line grunt for stop light action.  The 2.8 however has no top end.  They all complain that at 60 mph the motor is cranking out like a banshee.

The DOHC is not a dragster.  It's beauty is when it comes on the cams at 2500 or so.  Then it climbs faster than you cam grin.  In short the action here is on the road and you need better gearing to match, either the 5 sp or at least a 3.65 4 speed.

This is all just my opinion, and if I thought it was financially worth it, I'd stick one in.  I just know I'd get a crappy motor.

There are a couple around here for about 1500.  Here you get a motor that's been whacked out so you need to source wiring, ecm and likely accesories.

If you want I'll try to get a couple of sound clips I have of the DOHC.  They DO make you grin.

Gary

[fiero308]

Hi Gary
I would like to hear those sound clips; I am a sucker for technology and have been thinking long and hard about that 3.4 dohc but in the final analysis I am going to get a 3800 for my project swap.  I have read about the 3.4 and even bought a book on it (GM service manual) and that more or less did it for me.  The local shops want about $3500 to rebuild one .....NOT including the heads!  And you are very hard pressed to find ANY parts for them INCLUDING ordinary stock rebuild stuff; nobody makes cams for them, etc etc etc.
I talked to a mechanic who used to work at Surgenors on them; he HATES them....... nothing ever goes by the book and their time is always longer for any work.  Anyway, after all that, I went and looked at one (complete with a 5 spd!) and the engine noises scared me away.  175,000 and it was ready for a rebuild.  So......  
my two cents
gp

[CaddyRob]

I hear ya, with all of your points. But I am up to the challenge of this engine, and I would like a more unique challange then what the 4.9l will give. Im looking into a couple of local engines and will most likely be buying at least 2 right off the bat. One to drop in and one to work on for some serious HP. Its not the complication of the 4.9l that scares me, with the wiring and all. I just think this engine is more Me. Im in No real rush to get any swap done, and I will be taking my time, on any of the engines I choose.

About the my transmission selection. I almost think that the 4.1 is a better selection for this motor over the v8, purely because the v8 cannot rev. Im used to driving hondas around which odviously are more rev happy then the poor ol' Duke, or a 4.9l.

There is a couple around here in the 550-800 dollar range and I will be calling around for more.

Thanks for the heads up though, I always love a little constructive critisism! Makes me think more.

Later; Rob

[FieroDough]

hey guys!
Just an FYI.. I have the 4.1 awaiting to be installed in my 85 GT. This tranny should not be considered for anything other than dragging if you have a large motor. Or day to day driving if you have a Duke or for some insane reason you decide to swapp a 65 VW bettle engine.

The reason being is it will make you rev more than you need to, even with the DOHC engines. The 3.4 is ready to roar at about 2.2 to 2.5K RPM.  a 5spd isuzu will be much better geared for that. Trust me, it is always better to have the downshift option on the highway than to hear a gerble in sterioids behind you for a 3hr trip!


On the other hand (and the reason I want to use it on my 85 GT) is it's practically bullet proof. I would put money on the fact it can take more punishment then the getrag.

Cheers!
Eric

[fiero308]

Hi Rob;
are you going to be at the meeting?  I would like to discuss your 3.4 swap and so on with you; if you have a lot of info etc on it.  It is such a neat motor but there are problems too, just like everything.  I have done a ton of research on it and will try to put it on a CD if I can find the time.  It looks like I can make it after all so that is great.
I am still being wishywashy on the issue of what engine i will use and the 3.4 keeps coming back in my mind so maybe I am going to have to do it.
We can talk............
-Graeme

[CaddyRob]

Id love to make it to one of your guys meetings at least. Unfortunitly, Im a full time student with a Job too. plus I live 3 hours from Ottawa. Hopefully when the weather warms up and School is done, then I will make it up. Ive got some websites that Ive looked at. I think Im in love with this motor! It just seems more and more like thats what I want in my sleeper.

Anyways: Im still researching it, but it doesnt look TOO difficult of a swap, so its a go for me once this weather clears out and I can get my hands dirty again.

Later; Rob

[Sentinel]

Rob, one better than the sound clip, go here:

http://members.rogers.com/ottawafiero/pictures.html
and check out what the 3.4 will do on the solo run(Vid section)
careful if your dial up it's 10Meg