2.8 to 3.4 F-bird

[CJROTHY]

True, the stock FWD intake would point the Throttle body at the firewall. Unfortunate, but if the 3400 heads are vastly better than the 3.4 heads, then I am willing to bend the 3400 intake to my needs, possibly fab one entirely if need be.

If I am thinking about doing another custom intake, then I have to question whether the 3500 heads came in pushrod version, and would they bolt down to the 3.4 block, and are they better flowing than the 3400s. If the gains are significant enough, I can try that.

Doing this now for the 401 AMC. A real pain, but looks really mean so far.

[bszopi]

You can easily flip the plenum around and it will bolt up to the manifold and your TB will point to the front. Its been done several times before.

The 3500 heads (non-VVT ones) are pushrod heads, and yes they will bolt up to the 3.4 block. Do a search in the pushrod performance area for 3x00 and RWD and I'm sure you'll find all the information you need.

Like I said, its been done several times before by members of this site, so the information is out there on pretty much exactly what needs to be done.

[Guest]

GenIII heads worth it? Definatly.

But it's not exactly a "bolt on" deal, there are a few small custom parts needed. Starting with the 3.4 block, which is your best choice, you won't need a custom crank trigger like I did since I used a 2.8L block (no crank position sensor location).

The bolt pattern in the end of the heads differs between iron head and aluminium head, so some adaptation is needed there.

Throttle cable, Unsure on this one, I ended up modifying the linkage and keeping my stock throttle cable, seemed easiest at the time, I may change it in the future.

Exhaust from heads to at least y-pipe will be custom, in other words Headers or manifolds will need to be custom. You can modify headers to fit. The difference here is the exhaust port shape and bolt location is quite a bit different than the iron heads.

Hoses and some electrical changes will be needed.

You will need to run an ECM that is programmed for DIS.

Now I haven't confirmed this, but you may be able to use your existing harness and make a few modifications to it. This is the part most people have trouble with.

[CJROTHY]

Thanks for the advice! I will be putting the replacement block and major parts together this summer. As this progresses, how do I get permission to post photos? I tried UploadPic, but all that did was tell me I didn't have permission.

[bszopi]

Sorry about that. Try now! For some odd reason, it doesn't give new users permission. So I had to go through and give a bunch of people permission to use UploadPic.

[firechiken]

I got the wrong idea. I thought you wanted to use the intake from an f-body on the 3400 heads. Sorry If I got you a little f'd up with my info.

[CJROTHY]

After all this, now I'm thinking of doing somethign like the AMC V-8 intake underway:

The narrow V-6 would be a lot different, but might look just as cool.

[prodigy_16]

gmpp 3.4 replacement engine for trucks would be the easiest thing to do. and you can get camshaft from edelbrock for cheap to pump up the power.

[CJROTHY]

All too true. But I really like the lighter & better head design of the 3400 aluminum series.

Just as easy and far cheaper would be to get a 'yard 3.4 from mid 90s F-body, rebuild with +cam, and use my original accessories and MAF setup. But I want to put out substantially more than 200 hp NA, and should be able to. After shelling out for the unbalanced GMPP, I'll be unhappy with the puny 160 ponies it delivers, and have spent too much cash on the long block to modify lots further (and why spend $$ on engine bits I'll just want to throw away before installing?)

The 2.8 is now pushing 307,000+ miles and still plenty strong (realtively). Just drove back from Phoenix to Albuquerque at 80+ and 24mpg. I have some time yet to build a new mill and get it right before I have to replace.

Watch - I'll throw a rod tonight driving 3.5 mi home

[geoffinbc]

What are you talking about? The GMPP crate is not an un balanced motor. Specs on GMPP factory motors are extremly good. The cam it comes with is also very good. It is the exact same thing as a Crane 260 cam but with a narrower LSA. Also the 160HP is quoted based on a 2bbl carb with a carb intake and exhaust manifolds. If you have to spend the money on a full rebuild you will not come out cheeper than installing a crate. The Crate also comes with high strength valve springs with revised higher install height retainers.

However if you plan to radicaly alter the motor then the crate is not for you. If you are going to go with the aluminum heads and intake be prepared for some real down time on your swap. There are alot of odds and ends to take care of. Raven is one of 2 people I know that have actually done it.

[CJROTHY]

Didn't know the crate mill was that good, or that 160 was quoted using a 2bbl carb. My previous experience with production engines is that they can always use porting and better balancing. I wouldn't want to strangle it using the 2.8 intake, but if I was in a hurry, sounds like the wisest thing to do.

Fortunately I'm not in that kind of hurry, and I'd like to lose the weight in the heads. Thanks for the corrections.