Formula S 273 -- how to tell?

[clifftt]

I have a chance to pick up a 273 Formula S engine, but don't want to pick up a boat anchor. Little is known about this engine. Supposedly it runs, is missing the intake manifold. I'd like to drop it in my son's '64 1/2 Barracuda (273 2bbl). I understand the Formula S has higher compression pistons and a slightly hotter cam. Does anyone know how I can verify this is a Formula S engine? Serial #'s, casting #'s,....? Thanks for anyone's advise and wisdom!

[ehostler]

Keep in mind that if it has ever been rebuilt, there is no way of knowing about the compression ratio, unless you pull the heads and measure everything.

[cageman]

What year motor is it, thats a start.

[mopar413]

I remember my 65 cuda had painted valve covers with several rows of aluminum fins attached to them. But you dont know if someone may have changed them.

[DAHEMIKOTA]

The formula S had 10.5: 1 Compression. The pistons had a .140" dome on them. The distributor is a Prestolite # IBS-4013 dual point. Carb was a Carter AFB-3853S for manual and AFB-3854S for automatic. Valve lift with four barrel was .415" intake and .425" exhaust. The cam had a duration of 248* intake and exhaust with a valve overlap of 26*.It had heavy duty valve springs. Intake spring press. and length: Valve closed 83@1.69 Valve open 177@1.31.
Exhaust spring press. and length: Valve closed 83@1.69 Valve open 177@1.31.
Tappet clearance is: Int. .013 Hot and Exh. .021 Hot. Chrysler specified premium fuel for the four barrel engine. Horse power 235@5200 and Torque 280@4000. Hopes this is usefull. Dan

[DartGT66]

The original valvecovers should be black wrinkle with the aluminum inserts. Castings, other than the intake manifold, are the same as in regular 2 bbl 273's. The pre '66 heads had a different intake bolt angle, so finding an intake may be difficult and aftermarket intakes must be modified. There really isn't anything spectacular in the commando with an intake missing; hte only difference is the slightly hotter cam which propably will be renewed anyway during a rebuild (if it already hasn't), and the high compression ratio pistons which are difficult to obtain new (expensive).

[clifftt]

Thanks for the replies, guys. DartGT66 brings up a good point, that the pistons and cam would probably be replaced anyways. Probably a 1970's-80's 318 would be a better starting point, at least parts are available. Am I correct to assume these vintage 318's will bolt up to a '64 1/2 904 transmission?

[DartGT66]

I would go with more cubes, even consider a 360. It can be made to look just hte same as an old 273, it has got big port heads and the power producing capability + torque is way bigger than the 273's. I'm not so familiar with 904's, but I believe the least you need when installing a newer engine is a converter hub adapter. The converter hub and the hole in the carnk where it goes to, was smaller if I remeber correctly. I have seen adapter rings somewhere for this swap. Or, you can most likely change the clutc/drum assemblies and the pump + converter out of a newer 904, but I'm really not sure wether this can be done to a 904. The reason for doing it this way is the converter availability; not much is being offered for the old 18 spline input shaft.

[kick_the_reverb]

Agreed with DartGT66, start with a 360. Before you know it, a 318 rebuild will be the same money.

Ran

[DAHEMIKOTA]

The 273 block for the early Barracuda and Valiant had a notch in the left side to miss the steering gear. Just something to consider. Dan

[cageman]

I love my 273, I would put it up against a 360 any day.

I got my 273 out of a 65 Valiant, the lady drove it everyday since new, it started to leak antifreeze out the back and someone told her the block was cracked so she scrapped the whole car, kinda sad really, as it only needed new freeze plugs in the back.
I was going to bore it but the cylinders were withen spec for a standard bore piston, so I kept them and reringed it and new bearings were installed, I notched the cylinders for the magnum heads' valves to clear and it really runs strong. I have a 474 cam in it and magnum manifolds, I think I hit the combo perfectly.

It is in a light little a body, so the 273 really responds, I bet the 360 would not be any better, but I guess I am just in love with my 273.

[DartGT66]

I guess so too. The engine make power through the amount of air/fuel that goes through it, volumetric efficiencies do not differ very much. So, in theory to make similar power with a 273 than with a 360 you need about 1/3 more rpm. The amount of power a 360 can produce at 3000 can be had out of a 273 at 4000. That's in theory, there is more in it, that makes the difference greater, for example the bigger bore and better heads of the 360. A 273 is a nice engine and can perform very well, but if you do not have to consider weight/cubic inch, you will always benefit from bigger displacement.

I have never heard of a different block casting being used for the early A-bodies. I have installed 360's and 340's and 318's (and even 383-528 big blocks) in to early A-bodies, and I have had no trouble with the block/steering interference. They have all been with manual steering though.

[clifftt]

Cageman, with those magnum heads, is there a better availablity of intake manifolds? What are you running and what have you tried, what carb(s) have you tried?
And Dart66GT: are you really in Finland??!?

[DartGT66]

Yes, I'm from Finland, at the height of Alaska between Russia and Sweden! I have mainly built A-bodies, but have also always been keen on C-bodies, and now we've got a pretty serious C-body under work. Should be ready within htree months. Here is some pics of it: http://kuvablogi.com/blog/745/1

[cageman]

I run the cross wind intake, it has bolt holes for both heads, got it on ebay.
I am runnign a 600 holley dp, It has been a pain, real finicky on the weather, runs great one day, then the next with a 5 degree change, it runs like crap again, I am lining up the necessary parts for the thermoquad I have, but I need to make new linkage, and I need a different air cleaner too. I guess I just want to get 20 mpg with it, and I feel the holley is topped out at 15 1/2. we'll see.
I should just bolt it on and take it for a drive with no hood, just to see if it will actually run like Im told, or should I say have read. That is about my only option, for better mpg. It does run like a scalded dog though, I cant wait to see what it does in the 1/4, I havent raced any one yet, so I have no real estimate on how fast it is, But it probably is the quickest thing I own right now, but that aint saying much, as my fastest probably goes 14's!

[Billydelrio]

DartGT66, I am posting a picture of the 273's block notch that was mentioned in a previous post. This particular 273 has factory heads, which also have the matching notch. Notice that the head gasket I used does not match the notch. The early 318 LA heads have this same notch, although the 318 blocks do not.

The engine in the picture has a little 288 advertised solid cam along with some valve work. I put 11/32 valve stems with 1.900" intake valves. These are the largest I could use without notching the cylinder wall. I could not notch the wall on this engine because the top piston ring is high in the bore. This should be a really strong engine for an "old technology" 273.

Ah, who needs more than 300 cubic inches to run a 10.99 in the 1/4 with a 3221 pound naturally aspirated car? I guess I do as I have not done it yet! That is why I have another 273 engine in the works with notched bores that will accept the 2.020" intake valves of closed chamber W2 heads along with a weee bit of stroke.

[DartGT66]

Thanks, never seen one before; in my cars the original engines have usually been long gone. The '67 318's still used the same closed chamber heads as the earlier 318's, if I remeber correctly. Then in '68 the heads changed in to open chambers, both in 273's and 318's. I think the 273's lost their adjustable valve train and solid cam at the same time.

The only 273's I have seen running decently at the strip here was a '66 Valiant some 20 years ago. I think that had W2's; it run in the 12's. And a friend of mine has a high winding 273 in his '64 valiant, runs 14's easy with a four speed. And being from Finland, the 273's also have acted a part in our rallye history, the early A-bodies were quite competitive in Rallye here. Would have done even better, if they had been classified with decent brakes, and a bigger rear axle. There is currently one restaured rallye barracuda here, and it's 273 made well over 300 hp in the dyno despite of the strict rules. The valiants being lighter, were better rallye cars, but the factory insisited on usinig the barracuda in international rallyes. http://www.trianglemotor.com/fi/barracuda.htm

[clifftt]

Cageman: Who makes the "cross wind" intake manifold, or is that an old factory Chrysler manifold? Do you know if an LD4B Edelbrock without any mods? And Dart66GT: nice rallye Barracuda! If mine turns out looking half that nice, my kid will be proud! I'll post some in-progress pics later, as I'm at lunchbreak now at work.

[pishta]

crosswind is made by professional parts I think, and the LD4B is correct for a 273/318, the LD-340 was the 340/360 port size intake. The LD4B has the normal angles intake bolts, you may need to alter them slightly if you own the early 273 heads that have the different bolt angle/size.