My machinist spec'd out a comp 270H-10 for my "mild" 400 build. He swears this is the best low RPM grunt cam for this motor, given my gears, tires and trans Everything I've read on these specs say it's a "hot street cam" that makes power from 1800-5000 RPM. He says off-idle to 4500. Here's the cam card. What do you think?

 

It isn't all that big but 335 series engines favor split lift and duration. Why not just have one custom ground for it ? It's not all that much more money and you will get the best cam for your truck. Either way there are better off the shelf cams for a 400 out there that are split, I wouldn't use it just because of that.

 

What is the rest of your mild build? Intake, compression, gears, trans etc?

 

This is a no win situation. you aren't going to gain anything from a cam like that unless you up the compression considerably and if you do that your weak bottom end is going to be short lived. this is why the 385 series engines are what people do.

I have the 270H in my 390 AMX and in my opinion it would be a poor cam for a regular use pickup. if you have a hot rod 2wd thing going it would be fine. it's as far as you can go without a stall converter.

For the same money you can get a custom grind cam to fit your exact build and needs. I had this done just the other day on the roller cam in the 428 I built for my high boy. it's perfection for my needs. if you're interested contact me and I'll give you he name of the ford guru who will spec it out and sell it to you. it will be from comp or Lunati.

 

It's not a lot of lift but it is a lot of duration. Not sure how it would act. Need more info on the setup.

 

I hope you don't already have the cam installed. I agree with others that it's too much cam for your engine.
This is for two reasons: 1. It has about 10 degrees excess duration on the intake side. Then couple that with a 110LSA, which increases overlap. But that cam on a 114LSA would still be too much.
I'd suggest the Comp DEH265 or the Lunati Voodoo 10320700 for even more low end. .Look up their specs if you want to go with a different grinder.

Or have the Cam Research guys build you what they think best. www.camresearchcorp.com They're in the Denver area.
R.

 

Quote : Then couple that with a 110LSA, which increases overlap.

The LSA does not determine overlap, the valve timing does.

 

ok that would need a lot of timing as well as some stiff springs. You want something for low rpm torque. That grind would make for too many rpm, power too high, and be noisy on account of the ramps and stiffer springs. too much cam. I recommend a split grind. I don't necessarily agree that custom isbest on account that many "custom" spec grinds I have inquired end up being way too much duration and lift for my needs, those cam grinders know a lot, but when you ask one for high elevation work truck, hauling/towing steep mountain passes at hiway speeds and strong off idle performance they spec really big lift and duration to "flow more air in to increase dynamic compression by adding air to intake stroke to help fill the cylinder" This concept flat out doesn't work. A well matched intake to maintain velocity will help that. I am not brave enough to recommend without more info. The guys at crower have been the most helpful as far as recommending an improved cam.

 

True story. and with the heavier springs comes a better chance of wiping a lobe on break in. my 270H s more like driving a 2 stroke, all on the top end. not what you want in a pickup.

It is more expensive but a roller cam is worth considering, you get a better running engine with no cam break in fears and no zinc needed in the oil. I'm done with flat tappets.

 

Thanks for the replies. Lot of good folks here. It's purely a work truck, and when I say "work", I mean flat out ABUSE. before you say "well build a 460 then!" I'll remind you that the near stock 351m has lasted over 300k and 43 years. I'm trying to keep as much weight off the front of the truck as possible, so no big blocks or diesel "swaps" for me.

It's a 78 f-250 4x4 with 3:50 gears, np435 4 speed rolling on 31"s. I've got a small farm, it literally pulls stumps, hauls grain, pulls overloaded dump trailers full of firewood through miles of swamp and rocks in 4 lo, and spends most of the winter rocker panel deep plowing alot of snow in residential and commercial areas.

Oh, and it's my daily driver. Sees about an 80 mile round trip commute daily, so it does see some highway time a few days a week.

It needs to be a super low ROM grunt monster, while running super dependably. I'm liking everything I'm hearing about the 26EH..

My block has speed pro dish Pistons and will be decked. 70 Cleveland 351 heads milled. 400 crank turned 0.20, chamfered and polished with stock rods, baked, blasted, shot peened and resized. Block has been align honed. Press fit pins. I was pretty happy with everything until I saw the cam.

Keep the input coming, I'm liking the input and education. St this point, I'm seriously considering comp 26EH.

 

Given your description of use that cam is to big. I'd either go custom or something like the Lunati 10320700. I run a small Lunati in my 460 with a Performer intake and 750 Holley and the torque is nice. Stay small on the carb, a 600-650cfm would be great. The 260H or 255DEH would be good choices if you need to exchange what you have. The only thing that could dictate a change to something more aggressive is your static compression and how your dynamic compression would pan out. That could be why you builder chose that cam.

 

You might have some compression, figure it like align honing moves the crank towards the top improving quench, mill heads is another increase, and on and on. I would look at a 256 260 262 grind numbers. SPLIT THE PATTERN. More exhaust than intake on these builds. Ford even installed some "factory" split pattern stuff according to my books.

 

Too much cam for what you're wanting. I'll suggest the xtreme energy 262 which is what I run. Good compromise. That is the most duration I would run. Calculate your static and dynamic compression ratio for whatever cam you are eyeing. If you have high static compression you need a cam that will bleed some off or it will be a pinging SOB.

my static compression is a little over 10:1 and the XE 262 brings down the dynamic just enough to run 91 octane. Upgraded springs are a must. Here's a quick idle video.

 

Considering the cam has such critical importance to the engines performance and life, to me it makes sense to use a cam grinder who will talk with you directly- even modify the cam grind to fit your needs even better. With regards to price...the difference is nil- and typically you end up with an engine that runs better, gets better gas mileage, etc. and when especially the cam grinder takes into consideration specifics where you live including fuel blends, weather, and vehicle use! ....and with regards to the cam specs....well, it doesn't tell the whole story that you need to know to properly select the proper cam for your engine....remember, advertied lift/duration/lobe separation is just that- advertized and not the specific grind including ramp profile that is used on the cam!

Comp is a mass production (McDonald's type) company which - seems to have experience more cam lobe failures than most and places the blame on IMHO on everyone or thing but themselves...and this includes valve spring failure, cam lobes, etc.and it just does a cycle.To validate this point further as to the “McDonald’s environment” of which operate, check out this vid..... this is a "common issue with Comp
Valvetrain Failure:

FAIL Comp cams trunion- Rockwell hardness low:http://www.corvetteforum.com/forums/c6-tech-performance/3546465-fail-comp-cams-trunion-upgrade.html



With regards to their cams billets, I highly suspect that they are also using Chinese & they do not include Parkerizing their cams unless you want to pay extra for it (Parkerizing is a final and a crucial step to help break the cam in- a heated acid bath that microscopically etches the metal surface and adds a very thin layer of graphite coating which allows the cam lube to hang onto and penetrate into the cam surface during cam break in) unless you specifically request and pay additional money for it...… if you go with Comp, pay the extra!!!!!

One other FYI.....IMHO- If the cam is cut on Comps 8620 core and has a copper colored base to it, you should be OK. If it looks like a standard silver / metal camshaft all throughout you probably got one of their cheaper 5150 cores that are known for failure, plan on paying $400+ for the 8640 cores. I highly recommend Iskenderian & Crower & Chet Herbert & Lunati...all are family owned, been grinding cams for decades, and both will even re-grind your oem cam if possible- saving you even more $.

 

comp is OK under right circumstances. Make sure it oils good. BEFORE start up. Comp runs steep ramps and therefore becomes noisy on hiway or street. Not coolfor me, but some times loved. I have ran engines with comp stuff in them for years, been very good, just I wish they made a grind that had more advertised duration, less duration @50 and slightly les lift to mitigate the noise from steep ramps. I bet I have seen nearly 100 builds, from seasoned professionals to crate builds to do it yourselfers with very poor valvetrain geometry. This causes very accelerated wear amongst other problems, including very significant power loss. I see issues in that video, that hopefully get corrected before another comp product bites the dust. Comp is as good as any, if properly configured. Buy yourself a comp cam and spring kit, install and throw some original length pushrods in and set the valves to 1/4 turn and you are likely to grind your cam up from the first start up. Geometry is a very mis understood portfolio.