3.0 big bore?
 

I am getting ready to build up a 3.0 and am looking at the options. What all needs to be done for a bump in displacement, and what kind of cost are we really talking about?

I have not torn mine down, but was a, 80k mile engine so I expect the p&c's to measure out ok. I just don't want to leave power on the table if I can do it relatively inexpensive.

I am not going to build a 10k engine, but would throw in an extra grand for higher compression, or larger pistons.

Donnie,

You can make it a 3.2 by using 98mm P/C's and this is something you can sure feel. :)

I would be very careful about bumping compression given your summertime temperatures without twin-ignition.

Thanks Steve, I was wondering about the CR and how far you can go on pump gas. Twin plug is out. I assume the case spigots need to be bored, will I need 3.2 heads, or will the 3.0 heads work, and what machining would they need? If I need new heads, I may as well just put a little hotter cam in it and go with that to keep the budget down. End up with a mild carb'd 3.0 with headers. I think that would be around the 240 mark.

This is going in my 74, with 7:31 R&P by the way.

As you can see, I decided not to go forward on the 2.7.

I think 9.5:1 is about tops for CR on pump gas.

What year 3.0 are you working with?

Early SCs had larger intake ports and are more desireable if you're looking at a mod S cam upgrade. The 80's SC intakes can be opened up to get the most out of this cam.

I am planning a upgrade on the 3.0 in my 69. The P&C's should measure fine, but the CIS pistons need to be either notched for the S style cam, or a new set of JEs put in. IMHO, proper flowing heads and a more aggressive cam will provide the most bang for the buck on a short geared narrow body.

it is an '83. I Guess I should measure the intake ports before I go any further, new heads are not in the budget!

subscribing

I'm assuming you have a 3.0L to start with? (I see a 74 in your signature.)

With a 3.0L you can use the 98mm piston/cylinder set without boring the case spigots or swapping heads.

If you go further you will have to bore the case. 100mm gets you 3.3L, 102mm gets you to a 3.4L. Both of these require the case to be bored and it is generally recommended you chamfer the heads slightly.

Of course the larger you go, the more you risk detonation so careful planning on compression ratio is in order for street gas without twin-plug.

Hey Chris,

I just got an '83 3.0 with ~80k miles on it. It sat for a while, and the heads need looked at at the least. I figured though, I should build it now instead of open it again next year cause I want more juice.

So to do this I need:
My core cylinders to be bored and replated-any shop reccomendations and cost est.?
New pistons(JE with valve pockets, 9.8:1) ~800
Cams-I am thinking GE40
My webers to be set up for this combo
'78-'79 dizzy(I don't have one at all right now)
Headers-a found a set of triads I am going to use

Now about ignition:
I don't have the 3.0 engine harness, but do have the 2.7. Since I am not using the cis I only need the coil and alternator wiring right, so I could use my current harness.

The heads don't need any maching at all for this?

tks.
P.S I know this has been covered here, but you can't use 3.0 in the search so it ends up being 1000 posts about other things.

Donnie - EBS can bore and replate. I believe they sublet the plating to Millenium. They can also match up some new pistons to the bores. That new JE forging is supposed to solve a lot of the problems we've been hearing about with JE pistons, but I haven't heard any solid reports yet.

Aw, go for GE60s.

On the heads, you'll have to run the numbers to see what your optimal port diameters are once you decide on a displacement and cam. I've got a spreadsheet for that...remind me to send it to you from my home machine.

Ok, just heard back from EBS:

They need 3.2 core cylinders to bore, not 3.0, and the bore and replate is $895

for search ease in the future: three liter big bore

if you want to build a "budget" hot rod. Build a 3.0 around 9.5:1 port your heads a tad and use something like the ModS cam.

mine dynoed at about 215 rwhp with my 3.0 set up like this. ...that said I want about 20-40 more h.p. and a bit more grunt and am thinking of going to a high compression 3.2. -might be selling my p/c in the next few months.

Subscribing for information purposes.

Good luck with your project!
SmileWavy

Subscribing - good luck...

I am on the rebuild portion of a 3.0L and I believe I have learned a few things in the process. In the future I will probably release a spread sheet of the ideas that I had for this engine and what I settled for. The 3.0 basic puts out about 180 HP at minimum. I figure I will be at 220 when completed. I had the ambition of 300 HP with the twin plug's, PMO's carbs, S cams, and the end all mahle 98mm P&C at about 4500. I calculated about 18K for the upgrades which did not include the machine shop upgrades to beef up the case or little things to button the project up. I figured for that kind of money I rather have a 3.8 engine to start with, but of course that takes you out of the air cooled engines which drops you back to a 3.6 Tubro case for the best application. I finally figured that the 964 cams and SSI would be the upgrades for me, its cheaper by far and gives me a little more than the 180 HP. I have read about some radical 700 HP engines, but that is truly another project. Either way at 80K enjoy the ride a little more do some course events, that car is still young with a lot of life left in it.

good luck

This is just a core longblock to put in my 74, not a whole car. I am pretty well decided on the following:

3.2 cylinders bored to 98mm
JE pistons 9.8:1
port heads
Mod -s type cam, probably have camgrinder grind his DC40 onto my existing
Webers
Triad headers & a custom muffler
Will stick with the stock ignition

I figure from the estimates I've seen that should put me around 230ish, and with the 7:31 r&p it should be a lot of fun. It will probably run around 3500 for parts, and I will do the assembly myself.

Out of curiosity, did they explain this? I was under the impression that the 3.0 and 3.2 both used a 95mm piston. Is it an Alusil vs. Nikalsil issue? Difference in the design of the cylinder between the two?

The difference between the SC and 3.2 95mm cylinders has to do with the crush washer that seals the head. on an SC cylinder the position of it is too close to the edge of the cylinder when bored to 98mm (1.5mm of material removed). this leave a vary thin wall that will likely collapse when torqued or overheated.

There is more information in the archives.

Exactly the reason Jamie said.