I'm working on doing a build up on a 400 and I'm really unsure about my cam choice, so I'm looking for some expert opinions on it. My main worry is that it is too much cam.

I'm using a D7TE-A1A block that will be overbored 0.020" with stock D5AE-A2A heads (smaller 74.5cc compression chamber according to Bubba's site). I'm planning on using the flat-top pistons from TMI to give a compresson ratio of 9.54:1. For the intake I'm going to use the Weiand with a 650-700cfm carb (don't know make yet). For the valve train I'm going to use a Comp Cams K-Kit and get the Magnum roller rockers and new pushrods. The cam I'm thinking of is the XE274H (274/286 adv, 230/236@0.050, .562/.565).

Danlee's edyno tells me I should be get a dynamic compression of around 7.7 which should run on premium right? And Desktop Dyno is telling me I should be around 365hp and 450ft-lb, and the torque and power curves look fairly smooth.

For usage I'm not planning on using this motor for 4x4, offroad or towing. It will hopefully be going into a 20-30's Ford P/U hotrod.

So, is the XE274H okay for a cam or do I need to step it back a level or two? Or go with and even bigger cam?

 

I ran a Crane H278-2 (278/292, IVC of 72 degrees) with 10.2:1 static CR (7.7 DCR) and a 750 CFM carb and 351C-4v heads in my 400 before I changed to an HR with 66 degrees IVC and alloy heads.
I have a 2000 stall converter. My truck weighs about 4000 lbs, and the motor had plenty of power. In a light vehicle, you will be fine and it will have a nice sound. I would recommend some head work to help support that cam lift and RPM range. Of course headers are a must.

 

I'd back off to the XE262. It's still a lopey cam but it's driveable. The 274 won't really wake up untill you're well into the 2000 rpm range and it'll be a dog until it hits the sweet spot. Don't go over 9.25:1 static compression ratio with stock heads or you'll pound the bottom end out of the motor.

 

look at the other current topic i have (cr,pistons build yada yada)...it should convince you that you are on the right track. The 262 with 9.5:1 will give you 8.5+ dynamic which is way high and you don't have the squish with the open heads.

I think the 274 could be THE perfect cam for Tims pistons if you get 7.7 dynamic- and you should be able to run mid grade fuel with an outside chance of 87. I'd check with him too- (Tim - TMI-great guy). It may not wake all the way up early (ie not as flat as a curve) but you won't be lacking for power anywhere from idle to 4500. and you will scream at 3200 or a bit more. At that point i'd port heads as recommended above and increase valve size. Also maybe a single plane intake? hard to say and dyno numbers haven't been overly convincing either way (that I've seen)

check out the other thread. Same topic.

 

I'd say you are pushing the cam and compression for a streeter. You may have trouble with preignition and idle quality.

 

Thanks for the advice guys. I'm feeling more confident about the 274. Rough idle and no power till 2000rpm doesn't really bother me, my current car is like that anyways. I'll probably talk it over with Tim too when I finally get around to ordering parts.

 

Put some 4.56 gears in it and go.