[okcatalina]

im building a 400 for my 69 catalina. ive had the heads milled and block decked for a compession ratio around 9.25to 1 the heads are 6x 8s im gettin eagle rods and forged pistons i need help on deciding what cam to get? its going to be mostly a street car with an overdive tranny it has stock 3.23s in the rearend with an aftermarket posi.

[Mr. P-Body]

Flat tappet or roller?

It's no secret what I would recommend. A Comp "XE" grind is exactly what this engine calls for. It will depend on your actual purpose, as to which grind. Stock converter? Smooth idle? Is torque more important than high-end horsepower?

With this information, I can make a specific recommendation.

Jim

[okcatalina]

i want it to have most of its power from around 2500 to around 5500 to 5800 rpms

[ericwy]

Just watch your cruise RPM with the OD, a cam with little torque/power below 2000 rpm
will struggle and require deeper throttle and reduce gas mileage which it kinda the point
of having an OD.
Your 3.23 will cruise a bit under 1800 rpm with 0.70 OD ratio at 65 mph with a lockup torque converter.
With a 200R4 0.67 you are looking at 1700 rpm.

Just to give you a real world reference:
I am running a taller 3.08 gear with a smaller cam and it is boatloads of fun on the street.
I have a th700R4 with its deeper 3.06 1st gear which compensates for the 3.08 off the line. (like a th350 with 3.73). My cam makes good power all the way down to 1200 rpm so turning
1700 rpm at 65mph is no problem, (15" manifold vacuum, very crisp throttle response).

A bigger cam would benefit from more rear gearing to keep the cruise rpm in a more favorable rpm range.

[Mr. P-Body]

XE274H, but it will need a mild "stall" converter. 2,200 should do the trick.

Even better would be a "custom" flat tapet solid based on the XS282S grind. BEASTLY!

Jim

[okcatalina]

len from len williams auto machine has told me i should use a ram air cam with roads lifters but ive also been told that they are more of a higher rpm cam that doesnt have much of a bottum end that a bigger car like mine needs for street driving.

[chiphead]

I would stay away from the aggressive ram air III and IV cams because of the application and compression ratio. With 3.23s and OD tranny in a heavy car, you need torque from idle to 4500 RPM. Ram Air cams were used in lighter cars with deeper gears and higher compression ratios.

Select engine components that maximize torque at lower RPMs like performer intake and Q-jet. Ultradyne, Comp and Crower make great cams. Roller cam would be best, but high dollar. Some guys here like the cheaper Summit 28XX series of HFT cams. Do what you can to bring compression to 9.3 to 9.5 range, and use headers. Consider some head porting.

[71firebird400]

Go with Mr. P-Body's suggestion- he knows what he's talking about.

The RAIV cam would suffer from your low compression, there are better options out there for your engine.

[PONTIAC DUDE]

Yes a lower compression ratio can benifit from a tighter LSA to help low end power. Here ya go.

http://www.angelfire.com/fl4/pontiac...iminginfo.html

[okcatalina]

Originally Posted by Mr. P-Body

XE274H, but it will need a mild "stall" converter. 2,200 should do the trick.

Even better would be a "custom" flat tapet solid based on the XS282S grind. BEASTLY!

Jim

what vavle springs would be right for this cam the xe274h?
thanks for all the help!

[goatasaurus rex]

len williams is a great guy but this advice appears to be a bit "dated".

[hpp]

Originally Posted by okcatalina

what vavle springs would be right for this cam the xe274h?
thanks for all the help!

995-16 Comp valve springs.

[okcatalina]

thanks for all the help im goin with the xe274h

[chiphead]

I run the XE274 in a 400. It's a great cam for a street/strip engine. Make sure the machinist cuts the valvespring pockets for 1.7" installed height, and installs the correct screw-in studs in the heads. I would also suggest having the guides cut down for the viton seals. The XE274 requires an adjustable valvetrain and correct valvespring setup. Comp's K-kit comes with most of the valvetrain parts you will need.

I do have some concerns about how smooth the engine will run at 45-60 mph speeds with the OD tranny, XE274 and 9.2 compression. If you notice it "bogging" when the OD shifts, just drive it in 3rd to keep the revvs up until you get on the interstate. Then it'll cruise nice at 75 all day long in OD.

[71firebird400]

Figure out the installed height of your valve springs (depends on length of the valves, and if the pockets have been machined).

If it's a stock height, I'd recommend the Crower 68404 springs. The Comp 995 have been known to be a bit stiffer than they're supposed to be, although I've never dealt with them personally.

The important thing is to make sure you know your installed height and can determine your seat pressure (and over the nose pressure), too much pressure will hurt the cam, too little will cause valve float.

[okcatalina]

Originally Posted by chiphead

I run the XE274 in a 400. It's a great cam for a street/strip engine. Make sure the machinist cuts the valvespring pockets for 1.7" installed height, and installs the correct screw-in studs in the heads. I would also suggest having the guides cut down for the viton seals. The XE274 requires an adjustable valvetrain and correct valvespring setup. Comp's K-kit comes with most of the valvetrain parts you will need.

I do have some concerns about how smooth the engine will run at 45-60 mph speeds with the OD tranny, XE274 and 9.2 compression. If you notice it "bogging" when the OD shifts, just drive it in 3rd to keep the revvs up until you get on the interstate. Then it'll cruise nice at 75 all day long in OD.

i dont usaully drive any slower then 75 anyways thanks for the info ive already ordered the k kit from comp