1965Delta88

Hey guys,
I have a stock 425 in my 65 Delta 88 that has a spun rod bearing, so while I am taking the engine apart anyways, I wanna do some upgrades so I have more Power. I am pretty sure that I have the high compression version with the 4 barrel Rochester carb with I think 360hp stock. Now I am not sure if this todays horsepower or the old measurement still but it should be the the most powerful engine availible in the Delta, excluding the one from the Starfire. My goal is to get 425hp (onpe per cubic inch) and run the stock transmissiom and rear end (I have the posi). My budget is about 3000$ because I am still a student. Now to my questions:


Is the budget realistic for this kind of build?
How many hp can the TH400 handle without modifications?
What do you guys suggest I should do to reach my goal (Parts suggestions for intake, camshaft, ...)?
I also have a 750cfm Edelbrock Quadrajet that I would like to keep if possible.
Do I need new Pistons and rods? The engine has 149000 miles in it.
What should I have the machine shop do to the engine?
Do you guys know if it is possible at all to put headers on the engine in the Delta? As far as I know there are no headers that fit the Delta with power steering, so are there any you could modify or is there a kit to build your own? How many hp could you gain with headers compared to the stock manifolds? A friend of mine also suggested to have the machine shop weld the gap between the 2. and 3. exaust outlet in the manifold. Do you think that will help a few horses?


I have also never rebuilt an engine before, but my uncle is a mechanic. He just doesent know much about american engines regarding power upgrades because we live in Germany. My goal is to run the car on 98 octane pump gas and mainly drive the car on the street and take it to the dragstrip about 3 times a year.

I am happy to hear your suggestions and thankful for all your tips!!!
Greetings from Germany!

1965Delta88

You guys donīt need to answer all the questions at once. I would already be happy if you just answer one of them!!

76olds

This site has been hammered with new guys posting engine ?'s. It has been mentioned in so many other threads to use the search button to answer engine build related ?'s.
The engine guys that know alot about these Olds engine's do not seem to want to help newbie's out going forward.
This site will become boring in the near future. It will turn into a buy and sell site for many unfortunately.
My advice to you is to try and use the search button to learn as much as you can, then move on.
Afterwards us this site for entertainment purposes only.
This is my take on the Classic Oldsmobile site recently.
Wish you the best of luck with your searches and engine build.
Cheers
Eric

MDchanic

Okay.

a.) The rated 360hp are SAE Gross HP, measured without any accessories (such as the water pump) installed, and through an exhaust assembly that is essentially a set of headers with no mufflers.
The rating in the currently-used SAE Net HP would be less.

b.) Your 98 octane is our 93 octane.
Make sure that people in the US know this before they give you building advice.

c.) $3,000 seems a bit low, especially because you are in Germany, and your engine needs a complete rebuild.

Good luck!

- Eric

MDchanic

I should also add that adding roughly 100 SAE Net HP to your motor, without increasing your 10.25:1 compression ratio, so that you can continue to use pump gas, will require raising the power band considerably, which will require headers (possibly custom-made) a different intake manifold, and a different cam.
Once you have done this, this engine will not have much power at low RPMs, so you will need a different torque converter and a shift kit for your transmission.
You will also need a lower rear end ratio, as your stock 2.73:1 or 3.08:1 will be too "tall."
You will also reduce your fuel economy and your top speed, which may be important to you, living in Germany.

Are you really sure about this?

- Eric

1965Delta88

Thanks Eric for all this input. I really didnīt consider all the stuff you just mentioned because I have never done something like this. I definitely donīt have the funds and the intention to change something in the rear end and the transmission. The car is not my daily driver because you could never afford the gas here, it is mora a hobby and my connection to America. In that way, gas is not that important. But it probably doesent make a lot of sense to have more horsepower but a really doggy car at low rpms. If I only get a mild cam and a different intake do you think it would still be fun with the standart tranny and rear end? I would really love to get a nice muscle car sound from the engine, because V8 sound is the best sound ever and I wanna be able to smoke some tires. You think that is possible?

Fun71

Here's my opinion:
The 425 is a really good engine, with more than enough torque for what you want - don't get hung up on horsepower, torque is what makes the car fun to drive.

I would do a basic rebuild, ensuring that the final compression ratio is actually what you intend (some replacement pistons are a bit short on compression height, the aftermarket head gaskets are thicker than the originals, head combustion chambers can be slightly larger than rated). A lot of this can be compensated for by head and block deck milling to ensure the CR is what you want.

Check the heads to see what size valves it has and if possible, install larger intake valves.

Do some research to find out what cam the factory used, then once you have that info you can choose a suitable replacement.Many of the factory Olds cams were actually very mild, so a bit more lift and duration (matched to the compression ratio) can add some power without sacrificing driveability.

joe_padavano

Time for a reality check.

Given shipping to Europe and the fact that the 425 isn't exactly mainstream Olds, you'll be lucky if $3K covers a properly done stock rebuild.

1965Delta88

Thank you guys for the input!! The money thing is also what I worry about the most, but I think with a bit of tweeking I can somehow handle that and if it is waiting a little longer to be able to afford the upgrades. How can I actually find out which cam I have?
Do I want to raise the compression ratio or try keeping the stock in order to make some power on pump gas? Also I did a little research and I am pretty sure that our super plus has 98 Octane and I think octane ratings are the same in europe and America. Shell also sells the V-Power with 100 Octane at their gas stations.

cutlassefi

No, most likely your fuel is rated by the RON (research) method only, not the R+M/2. That's Research and Motor added then divided by 2. Normally that equates to about 5-6 numbers less than our rating.

How about E85? Might want to look into that, normally way cheaper than your premium.

MDchanic

You did too little research. You need to trust us on this one.

If you build your engine to run on 98 US octane (98 AKI), instead of 98 European octane (98 RON), you will be building your engine again very soon.

- Eric

1965Delta88

Thank you guys for correcting me there. I did some more research and you guys are right. So what do you guys think, I am thinking of rebuilding the engine stock compression, a little more agressive cam and something like an edelbrock torker intake but probably keep the stock manifolds for now, at least until I have the money to afford custom headers. Is that really gonna make the car that worse to drive? Is the tranny gonna be able to handle that? I know I am kind of asking the same question with a little more detail, but I just could not figure out if you guys are trying to tell me I should go stock or I am not gonna have fun with that engine. As for the gas: it is not a daily driver, more a weekend projekt, so I dont care about gas prices that much. Thank you guys very much for helping me out!! I really appreciate it.