555 heads with double notch 011 348

[Tim]

After taking delivery of my 348 today curiosity got to me so I took a head off to have a look. Here is what I found. Block is 011 348 date code may61 double notch. Heads are 555 dated July 61, everything is time correct and doesn't look like it was ever apart. I'd like to get 350-400 hp. I know I can gather up the info from past posts. Any ideas? see pics of valves

 

[Don Jacks]

With 817 heads.a mild cam,high compression pistons.your goals are possible,with those heads,no way.You can find 333's upgrade to the 817 valve size ,and make 365-370 hp with out too much trouble.An 11-1 piston,based on Jim's research,will net about 10-1 with the 817 car head,9-9.5 with the 333 head,when used on a double notch block.

 

[Tim]

What about the crank and bore Don? Just leave it 348 stock? Tim

 

[oldskydog]

Do you have a pic of the intake ports/runners on those heads? The dates are late enough that they might have the improved bigger runners like the 333's but lacking the combustion chambers....possibly an interim version.

 

[Tim]

 

[Don Jacks]

Stroke is always better,Tim.Don't bore it more than necessary.What are your plans for this engine,as in what's it going in,trans type,rear gear,ect?

 

[Tim]

It's going in a 66 SS. It has a 283 now. I have a 2 speed glide and a 12 bolt rear end that came in it factory . Ratio will be changed and add a posi trac. Trans I can get upgraded for the added hp/torque Currently it's a 336 ratio. I'm thinking 30 over. Cleans it up and adds a bit of compression. 409 crank for stroke, car is heavy so I need more than the go cart 283 has.

 

[DonSSDD]

Don, any Eddy heads and intake that would make sense here?

Don

 

[Don Jacks]

Tim,The absolute best thing that car,performance wise,is lose the Powerglide!Even a simple TH350 swap will feel like you added 50 hp.to the engine.The best swap would be a 700r4.Leave the 3.36 gear,and stock size tire on it for now.What this car needs is torque in the 1500-3600 range.With this double notch,it's going to be hard to make anything over 10-1.Use a smallish cam,817 heads[a little bowl work always helps],an edelbrock dual plane single carb manifold,a carb in the 600-650 range.In case you don't already know,to put this engine in your 66,you're going to need to find a set of 65 409 exhaust manifolds,or make a set of headers,and the 65 409 oil pan.These parts can be hard to find,and pricey,but are mandentory.

 

[Don Jacks]

Don, any Eddy heads and intake that would make sense here?

Don

In my opinion,Don,no.The eddie heads are all large port,large valve heads.Top that off with the fact that the area around the valves is almost as big ,cc wise,as the 333 truck head,meaning less compression.Maybe if you put some kind of blower on it?

 

[MRHP]

Did someone say blower?

 

[Tim]

Don Jacks, what does a 30 over bore do? It should make compression better??? I have access to a th400 trans, will that work? and I may have to modify the truck oil pan on it to fit. Luckily I have a rolling chassis to work with. Headers I may have to make which isn't an issue. I didn't know there was an issue with this stuff but I'm sure I would have found out the hard way on the fit process. 817 heads I'll keep an eye open for. I have a j1157 tri power intake to get rid of. Maybe somebody can trade me. It has 2 of the original carbs the third is aftermarket.

 

[Tim]

Don, can the 555 heads I have get bigger valves put in them? Maybe it an alternate option to buying 817. Spend the money on the ones I have.

 

[Don Jacks]

The overbore just makes certian[hopefully] that the bores are straight,round,and honed properly honed for the ring type being used.As to the 555 head,try to locate a 379 head to visually compare the two heads.If the port volume appears to be the same,,then I wouldn't.If the 555 port volumes are bigger,then yes,I'd try to use the 2.06-1.72 valves.Yes,the TH 400 will work,but its internals are heavy and rob a bit of power.On the plus side,with minor beet ups,you'll never break it.All of the head numbers that we've discussed here are concidered small port heads,but the main differances are that the port volume on the early stuff,like the 379,and 702 is very small when compared to the 1147,817,and even the 333 truck heads.The later heads mentioned have bigger ports than the other heads can be ported to without ruining the head.Port volume =power.

 

[Tim]

Ok so the trans I have, my neighbor will trade me for firewood!! I think DonSS May have something to compare. Maybe oldskydog can chime in with a measurement. I'm trying to get an idea what to shop for in the next few months to get it built.

 

[MRHP]

My 333 heads are huge compared to my 702 heads.

 

[Tim]

These 555 heads look big, there is very little combustion chamber, they are flat just the Indents for valves.

 

[Don Jacks]

When looking at the picture that you posted,and comparing them to my 817's,those exhaust ports look awfully small to me. Yes,if you're used to looking at small block heads,the ports look huge.Don't throw away that 'Glide,as it makes a good core for a racing transmission.

 

[Tim]

The 283 and the glide are documented original to the car. I may just treat them and put them away. I just talked to DonSS. He has a set of 333 heads to compare to. If they have the same openings I use them? If not look for another set. I should be able to use the rockers off the 555's if I have to buy naked ones?

 

[Don Jacks]

If the rockers and balls are in good shape then reuse then.Yes,if they have the same size ports,why not,if not then look for something else.There is very little knowledge around about the 555 head,but Cecil's point that they MIGHT be an interarm head to be used with a double notch block jut prior to the release of the 333 head is possible.