Sensible improvements without new internals.

[Johnfm]

What are the sensible, realistic gains to be expected by, say, just changing cam and installing appropriately tuned bike carbs* to an otherwise healthy and standard big valve headed twinc?

Is around 140 BHP realistic?

*Car has twin Dellortos at present, but a couple of owners I know swear by replacing with 4 x bike carbs like these:

http://www.boggbros.co.uk/gallery6.html

[rgh0]

You cant get much more power by just changing the cam or carbs on the standard twin cam.

Well tuned webers will produce as much power as you can get from a set of mikuni style bike carbs.

You cant get more lift without changing the valves and springs as well and without more lift you don't get much more power and you put a big hole in the midrange torque if just put in a longer duration can of the same lift.

The combination of sprint cams with webers or dellortos is close to what you can do in hp terms without getting inside the engine.

cheers
Rohan

[Pistacchio sprint 72]

Having the flywheel lightened does not give more hp but it makes your engine revs higher more easily.

For me it is a simple mod I love!

[elansprint71]

Have you considered looking in the archives on this forum?
Presumably the "couple of owners" whom you are acquainted with, have the advantage of us here, with respect to TC engines.

[twincamman]

OK.I just visited your site ...nice work... suggest to your client ...what are you looking for here the stop light drag strip or a road circuit ?.... Really a stock 110 HP motor in a 1500. Pound car with an 18 guage cobbled up chassis is just about all the car can safely stand There is the case of upgrading brakes , tires wheels that can stand the increase in power ....it's a whole package not just a bigger engine and a heavy foot ,the stock set up. should be fast enough to beat any body ...IF YOU KNOW HOW TO DRIVE .....in the case of taking on a Mustang or Camaro you will beat them in the corners but you will lose in the straights!...If you are really serious about going fast enroll in a race school and learn just how much there is to driving quickly and save some money ..[and remember racing on the street ain't racing so put it on the track before you spread your car and yourself on the public road and create an instant yard sale /organ donor clinic...Ed

[Jeff@Jae]

I agree with Rohan and Pistaccio Sprint about simple modifications without going internal. You might also find that carefully going through the whole cam timing operation and setting them accurately with offset dowels to a true 110 degree MOP can have a huge positive tuning advantage. A lot of these engines have the standard marks lined up but in fact the cams are off true timing by quite a bit. Some engines feel "soggy" and others have a powerband at one end or the other of the RPM spectrum only. Time the cams, adjust valve clearances, carefully tune the ignition/distributor and the D'ell Ortos and be sure the car has a nice set of exhaust headers/exhaust system and you might find it's a whole new beast.Oh yeah, change the airfilter element to a K&N element as well.

[twincamman]

oops misconstrurd the request.......Twincamms are sensitive to timing so the cam timing must be spot on with each other and the crank timing ...this includes points and plug gaps and distributor timing ..Carb balance and jetting are important also ..commpression and balance also...lightening is a subject for debate..ed