neuroclast

Right now I'm running a XE274H (230/236 duration 480/490 lift). I have a 700R4 with a 2800 lu torque converter and 355 gears, and trickflow 23 heads with around 11:1 compression.

Mainly I'm wanting a little more power, but I'm wondering if I can use this new cam without getting a bigger TC? It says for 2800+ stall so I would think I'm fine but I don't want to LOSE speed from having too small a TC.

Also, will I have enough vacuum to keep things running with the bigger cam, or will I have problems with the low (~650rpm) idle of an auto in gear?

Oh and one last thing, on my current grind sheet for my cam it lists it as XE274H-10. The -10 being 4 & 7 swap firing order. Why the hell would you do this, and do I need to make sure I get another with those swapped?

Thanks

The Money Pit

I ran the XE-284 in my 406 with a 2200 stall, and it would idle in gear at 650 rpms. I thought the XE-274 was a better match for the overall combo I had, but was also looking for more power. The XE-274 also idled like a stock 350, with very little "attitude".

Remember though, not everyone's opinion will be the same. What I think is mild, some would never consider streetable............The Isky solid I run now tips 7000 rpms with ease, and shakes the car nicely at the lights.

BKbroiler

If your present cam calls for 4 and 7 cyls swapped in the firing order and you change to a cam for conventional (1 8 4 3 6 5 7 2) firing order, just change the 4 and 7 wires on your distributor cap. I think the theory is that since cyls 5 and 7 are next to each other in the block, when they are also consecutive in the firing order there is some loss feeding and exhausting both cylinders.

LFZ

I had the XE284 in my first 383. Personally, i thought it idled way too rough even at 900rpms, couldn't cruise or do anything below 2200rpms..it wasn't a very streetable cam for my taste, but it revved like a **** for a hydraulic. In my opinion, that cam with a 240+grind is too big for a 383. I have a XR288HR now and street manners alone was enough for me to switch.

larrywalk

According to literature I've read, the reason for the 4-7 swap is to decrease the dynamic vibrations in the crankshaft.

neuroclast

That seems like a good setup, but since my current cam is hydro flat tappet I'd like to keep it that way. I don't think they have a HFT cam with that profile do they?

63mako

Why? If your changing go hydraulic roller. The HFT cams with fast ramps are like a time bomb in your engine. The question is not if it will wipe a lobe but when and will it take out the rest of the engine, probably so. The extra $600 will get you 40 or 50 HP and better street manners over a similar FT grind plus piece of mind. Pretty cheap upgrade in the big picture.

neuroclast

They are a lot more expensive. I can get a new HFT cam for <$150. A new roller cam+lifters is like $800? That's a bit of a difference, one I'm not willing (or able) to pay right now.

baxsom

not to mention you have to do that thrust washer thing

still not sure what that all is