Camshaft selection

[Xenon]

Wrote to comp cams for a recommendation and this was their reply:

A cam that best fit your mods is our xtreme energy cam (12-262-4)specs are below. The cam will have to be on a small base circle to clear the stroked out engine.


The cam will help increase power and torque, excellent throttle response, also will have a nice lumpy idle
The cam will be 218/224 @ .050 and the lift is .464/.470 on a 110 LSA


If not done so I always do recommend in upgrading valve-train to protect your investment. The upgrade helps in getting the most power from the engine/cam and keeps its safe. We do offer a cam kit which includes(cam,lifters,springs,retainers,locks,seals ,timing set)



What do you guys think of that?

[Fast355]

Wrote to comp cams for a recommendation and this was their reply:

A cam that best fit your mods is our xtreme energy cam (12-262-4)specs are below. The cam will have to be on a small base circle to clear the stroked out engine.


The cam will help increase power and torque, excellent throttle response, also will have a nice lumpy idle
The cam will be 218/224 @ .050 and the lift is .464/.470 on a 110 LSA


If not done so I always do recommend in upgrading valve-train to protect your investment. The upgrade helps in getting the most power from the engine/cam and keeps its safe. We do offer a cam kit which includes(cam,lifters,springs,retainers,locks,seals ,timing set)



What do you guys think of that?

Too much cam for a vehicle as heavy as yours with a stock converter and only 3.73s. I would look into something more like this. It may have to be ground on a small base circle depending on connecting rod clearance.

http://www.summitracing.com/parts/cc...make/chevrolet

For mileage and throttle response this would likely be even better but would run out of breath by 4,500.
http://www.summitracing.com/parts/cc...make/chevrolet

[Xenon]

For mileage and throttle response this would likely be even better but would run out of breath by 4,500.
http://www.summitracing.com/parts/cc...make/chevrolet

well I've been looking around more and I really like this one you suggested.

How do I know if I need to have it ground on a small circle? And do I need different springs, pushrods or anything? Or will stock be ok?

thanks.

[streetperf]

Xenon,
With all the info you have received on your 400 TBI engine, You should be able to make an somewhat decision. I don't know how many dollars you have to spend on this project but to get gas mileage out of a 6500# vehicle that has the areo package of a brick, is going to be very difficult. Being a 400 is a good start in that vehicle, most chev camshafts are ground for a 350 application in the catalogs, unless otherwise stated, so in a 400 the cam will seem to be smaller due to the larger displacement of the engine and torque output. Therefore you can use a Slightly larger cam duration to achieve the desired results. For instance, a 204 duration camshaft works very well in a 350 application, in a 400 you can use a 209-212 and get better results and approx same power band increased toque, hence the increase in CID, and Stroke of the engine.
You have stated what heads you have, example- casting number. If you want to change them or not, again goes back to dollars. Newer heads work better than 80's open chamber emission heads by far. As was stated earlier install a set of vortecs and go. However that will involve a new intake manifold. Again dollars.

If I were you, and I'm shooting in the dark here. If you don't have allot of money to spend and you don't know how the expected results will turn out for you, I would be conservative on my changes. A camshaft that has been previously recommended be purchased with lifters, installed, tuned and test driven for results over a period of time.

[1project2many]

I have posted some links to a DIY type modification for the stock TBI intake that will help improve airflow. It will still fall short of what a 400 wants but it can help. The same would apply if using the TBI Vortec intake. Along with opening up the bores, this will help improve flow as engine rpm increases.





Ultimately, the rear gear and trans ratios should be in line with the cam's powerband. Trying to change intake, exhaust, etc when the cam is not appropriate is just an attempt to bandaid the problem.