273 to 318 swap 65 dart vert

[Sppike Mike]

I've got a 65 Dart Vert with a 273 with 360 heads and a edlbrock performer 318/360 intake. 1406 600 cfm carb and a really lopy cam. It's the car in my profile picture. I bought the car and have no back ground info on the engine build. Ive got it running good but it seems to be all bark and no real bite. step on the gas and it makes lots of noise but doesn't really pull. I was thinking it's due to the stock 2 into 1 exhaust. I plan on running fenderwell headers to try and make it breath better. From what I was told the bottom end of the engine is stock. If after I add the headers it doesn't improve enough I was thinking I might build a 318 short block so I can use the 360 milled heads on the 273. What other things do I have to do to make the built 318 work? will it swap right in motor mount wise? What about the torque converter? There's a 904 tranny behind the motor. Any help would be very appreciated. Thanks

 

[Hell_Fish]

The 360 heads could be giving issues on the 273 because of valve shrouding.
The answers on the 318 can be dependant on year of 318. It will mount up to the motor mounts.

 

[BillGrissom]

Isn't 360 heads on a 273 a bad idea? Doesn't that lower compression a lot? If you don't get much torque on the low end, that wouldn't be a problem with the exhaust unless there is a major restriction. I have seen mufflers clogged up. A vacuum gage can indicate that problem (slow rise after throttle), or if you disconnect it try blowing thru it with a hair dryer. Otherwise, it could be a bad O/F ratio, low compression, weak spark, ....

Horsepower is what you get at high rpm with the engine screaming like a banshee. It doesn't get you quick off a stop sign, unless you rev the engine with your foot on the brake as drag racers do (wouldn't that look stupid?). Most drivers notice low-end torque more, which is why most V-8's came with 2 barrel carbs.

 

[273]

360 heads on a stock bottom end 273 would be a huge drop in compression and to big "ports for the build and probably lack of gear and stall speed, as for the swap it should be a bolt in other than the torque converter smaller nose on the early one get engine and tranny.

 

[Sppike Mike]

Ok so here's what I do know. It's a pretty common performance mod on 273/318 LA engines to use 360 heads but mill them .50 to bring the compression up. I know I need to pull the engine apart to determine if this has been done. the person I bought this from got it from his uncle who is now deceased. Eventually that's what I'll do. I most likely will look for a 360 and rebuild it to drop in and then go through the 273 on a discovery mission. But 1st I'm gong to build some fender-well headers for this car. I am hoping that will help. This engine is just a temp for this car. I really appreciate everyone's help with this. Thanks a ton!!!

 

[RedFish]

I'm sure anything you use will be better than the stock early A exhaust manifolds.
Nobody has mentioned rear gear though. You have to get the horses to the pavement.

 

[65cudalover]

I did very well with my 66 cuda and now my 65 cuda formula s w/ 318 4bbl done with mild cam and head work. the 66 ran high 13's at track with trans work and was soon the be going faster after putting in a nice built 8 3/4 rear end as I was going to go after making motor faster when man backed out of his drive into car on the way home from track! That was many years ago! Now my recently restored 65 formula s is ready to go with basically stock 318 4bbl set up and nicely done trans. It passed down the quarter only a few times in the mid 15's without any other adjustment to it yet. It does also have a more modern electric spark set up as my other cuda had, one easily does this as should for a little extra hp and efficiency. I would not go after too big of headers on the 318 when you can work within its own set up and go fast without hurting engine and quality or driveabiity on the street.....JMO

Bye the way too my friends in the Chicagoland and Great Lakes Dragway area I am soon to be coming back!!! I am accepting a job back in the North Chicago area and me and the 65 Formula S will be there by the end of Summer!!!! I am recovered from my epilepsy issues and driving again so look out here I come!!!!!!!!!!!!!!!!!