Mopar Muscle Association UK

Hi there,
My name is Chris Wilson and I am a brand new member and have just bought a 1964 Dodge dart with a 273 engine which is a currently a race car sometimes raced at the Goodwood Revival or Members meeting which I plan to continue if possible.
I am looking into the regulations and have yet to have a full description of what has been done to "my" engine already. However I believer that a standard block can be bored and stroked so long as it looks standard externally and it doesn't change the capacity class I.E. 2001cc or over.
Can anybody tell me if it is possible to get a reliable circuit race engine of over 4500cc starting with a 273 block and if so how big can it go.
Also the heads can be changed as long as they are of a pre 66 type.
Please excuse me if these are stupid questions but as I say this is new to me.
Cheers
Chris Wilson.

Hi Chris, good to see you joined up and welcome to the club.

I was thinking about this after we spoke earlier and wondered if a 340 might be the way to go? Or if the 273 block would be suitable, whether 340 internals would work? They are all LA engines but I don't know how different the 273 block looks to the 340 if at all but the 340 was developed with racing in mind. I had one in my 1973 Challenger and I was impressed when I rebuilt it, it had all the right bits.

More info here https://www.allpar.com/mopar/mopar340.html
http://www.tunakiller.com/340_Engine.html
https://en.wikipedia.org/wiki/Chrysler_LA_engine

There will be other along shortly who know far more than me.

Cheers, Martin.

Thanks Martin,
I appreciate the help.
I know that the engine would have to be exactly the same externally but I think internals are pretty free. Obviously I will make sure of the rules before any build takes place.
Cheers
Chris

any pics of this car? sounds interesting

Hi There,
I will get some and post them for you but it won't be 'till after the weekend I'm afraid as I'm just off to Silverstone.
Cheers
Chris

AFAIK , all small blocks will look very similar externally, so you could go to 340 or 360 (340 is the better engine), might just need to have the older style 273 rocker covers.
I only have 318 experience so there will be members who can confirm this, but they are all LA engines and within reason are a nut and bolt swap.

early 273 have different angle on the inlet manifold bolts so inlet manifolds don't interchange unless you machine the bolt holes all cranks and rods are the same for the 273, 318 and the 340 but not the 360. early 318 and 340 cranks are internally balanced. Late 273 the aussi ones I think are external balanced

This is going to have to be FIA Homologated this that and the other I assume? That means the correct numbers on the block and heads, so not much scope for skullduggery. I've long since forgotten all I knew about 273's having not built one for the last 30 years. Stroker kits are available for 318's which share the same crank and rod length so something might be possible there. The issue with all standard Chrysler engines is the ports in the heads are already a bit on the small side for the standard bore so stroking without a head swap tends to produce a stump puller which isn't what you need. I would talk to Rob Loaring at ICE who is an excellent engine builder with circuit racing experience.

I agree with Blue the heads are the problem

You cant really put the bigger 2.02 valves in the 273 heads as you have to notch the top of the cylinder boar. Been there done it

And as the small bore would shroud the valve so much it makes me wonder if it would actually be much of an improvement.

I think you'll find you'll be limited on what you are able to do within the regulations.

so only valve sizes available in period, no strokers, a 40 thou max overbore, no roller rockers etc. you can change crank and rod materials but only H beams, no I beams (or the other way around, can't remember which), no flat-plane cranks and no changing the firing order. so basically a 273 with 40 thou overbore is the max cc you are allowed.

ask Peter Knight as I'm sure he built your engine.

you can fit a larger engine but it wont be legal for most races.

when your car and the '65 Barracuda were at the Revival together a few years back they had the same engine information plate, fitted by the engine builder, giving ign' timing etc. the Max advance was different for both vehicles but I would have thought they should have similar engines. (different compressions?)

the Barracuda used to have a 'cheat' engine and was a front runner at the revival but that was soon stopped.

check the old Revival vids on youtube.

Apart from casting numbers, what else is actually checked? Surely nobody will be stripping an engine for inspection or do they? Everybody thats trying hard enough cheats and it's only cheating if you get caught...
I know next to nothing about circuit racing so I'm interested to know whats what.

Surely nobody will be stripping an engine for inspection or do they?

the year they had a Mini only race at Goodwood every car had to be presented for Scrutineering with the cylinder head removed.

I used to look after a '63 Corvette race car and had to take the rocker covers off for inspection every time. That used to have a cheat 350 engine with false casting numbers which I had previously removed and fitted a period correct 327 engine. also the regs stated that being a '63 car it could only run drum brakes as that was all that was available for the Corvette in '63, even though it was up against '65 cars which were allowed disc brakes. it was a few years before they allowed it to runs discs as they would have been fitted to a '63 in 1965!

if you get caught cheating thay will still allow you to race that meeting though you'll find you will not be invited back again.

Hi Guys,
I'm just back from Silverstone and amazed at all the info and responses I really do appreciate it.
I will have a read and try to digest what's been said.
I should point out that I will push the rules and regulations as far as I can but I can't do any cheating, it's more fun to get somewhere by the legit route.
I hope to do the help some justice!
Thanks again.
Cheers
Chris