does my cam choice fly

[baxsom]

i admittingly do not know enough about choosing cams to make this decision without asking.

in looking at their website this setup looks like what i want but i wanted to make sure

here is my setup
454
torker II intake (wont change for hoods sake)
speed demon 750
headers
67 L36 427 heads
2500 rpm stall convertor
3.55:1 rear end

i am thinking of this cam set.
COMP Cams: Xtreme Energy™, XE274H <BR> Very Strong Mid-Range Torque and Throttle Response

i like the comp cams set because it comes with everything necessary from cam, to springs, to lifters, to timing chain, to pushrods etc etc.
it takes the guesswork out of what supporting parts you need to go with the cam upgrade.

i have first hand experience with the XE lineup in my old mustang and was very pleased with it but am open minded enough to try a different version out there if necessary.
thanks

 

[Ed's 1970]

Have u calculated your final compression ratio?
This is a big influence on the cam choice and how detonation sensitive it is. With iron heads, this limits your compression to around 9:1. With aluminum heads it is around 10:1 because they shed heat faster than iron.

The biggest factor in making power is the heads. Going with modern cylinder heads will really wake up your 454. Another option is to port your existing heads to make more power. Going aluminum is a great way to go because stock iron heads are so heavy. I am currently building a 540 engine and went with Merlin alum heads. They flow good and the exhaust ports are in the stock location unlike darts and afr's.

Picking the camshaft is the hardest part. I think going milder rather than more radical is the way to go. More vacuum, nice idle, etc.

 

[Rodney Gold]

It will work well , if it lasts , I will never go for a flat tappet hydraulic again as I have lost 2 cams in 2 diff cars in the last yr , evidently there are problems with oils , lifter mnfgrs etc etc. I would go roller hydraulic and perhaps 1 stage more aggresive. You already have the stall and rear end and an engine that puts out prodigious torque , you could proably do with a little less power under 3000?

 

[Crimson Thunder]

I agree with Ed. I would pick the next smaller cam than the one you picked. I like street cams to be no larger than the mid 220's at .050 dur.

 

[baxsom]

the next smaller one is the xe 268 which apparently a lot of people here have. i was looking at that one before the headers and converter upgrade.

i am not sold on the xe line though, i have read a lot of them are wiping. in contrast though i put a xe256 in my 302 mustang, used rotella t with comp cams break in oil, 3000 rpms for 20 minutes right at start up and it is running fine.

there is also the high energy and thumper line.

comp cams recommended over the phone the xe268h.


as far as the final compression ratio. i know stock the 72 454 had 8.5:1.
it no longer has the stock heads though. it has heads off of a 67 L36 427 which supposedly has smaller combustion chambers so i am not sure of the compression ratio now. id like to know honestly. that info would indeed help in cam choice but i am not sure how to calculate it.

 

[73shark]

Might check in a TRW piston catalog. When I was picking a piston to use, I wanted to up the CR from 9:1 to ~10:1 w/ my stock heads. Their catalog shows different CRs for different head combustion chamber volumes. As it turned out, the 11:1 LT-1 pistons were the ones we went with.

Someone here can probably conjure up what your '67 head volume is.

 

[baxsom]

on this site, it shows the specs for various BBC heads
Big Block Chevy Engine Parts Identification

my heads are casting #3904390.
it says that they are closed chamber heads 98.4cc

oem 454 heads for a 70 to 84 454 say open chamber 113.0cc

whatever all that means

coincidently it also has the grind information for the stock cam.
stock 454 cam is
lift 460I/488E
duration 213I/217E

 

[73shark]

Find a parts store or engine rebuilder that has a TRW catalog and find your piston and see what the CR is w/ the 98.4 cc head is. Since you didn't say what your pistons are, it's hard to say.

BTW, I've read where the open chamber head is a better performance head than the closed chamber heads.

 

[baxsom]

i really dont know what pistons are in it. i am going to guess stock. but since somewhere down the road the heads were changed out there is no telling what is in it now.

 

[73shark]

What year is your engine?

 

[baxsom]

it is a 72 4 bolt main.
the stamp by the tranny on the drivers side says so.


it is definitely not the original engine.
the VIN tag by the passenger head is blank.

 

[73shark]

I guess you're pretty much stuck 'til you pull a head and cc a piston.

 

[baxsom]

ok, i finally got around to getting to a machine shop. according to them without pulling a head and actually looking the difference in ratio from the 454 heads to the 427 heads would only be .2-3 points so i was told a good comp ratio to use for cam choice would be anything from a stock head choice of 8.5:1 to 8.7:1.

so that being said,
with the stall, headers, and gear ratio i have already mentioned which would be the better cam choice

the xtreme energy xe 268h
the high energy 268h
or the magnum 270h.

 

[Crimson Thunder]

Have you downloaded Compcams Camquest yet?(its free on their website) It will help you pick out a cam for your car. From the three cams you listed i would go with the Xtreme 268 cam,it is the newest design out of the three and has the most lift.

 

[baxsom]

i tried compcams camquest.
it recommended different cams each time i ran it with the same specs.

i originally was looking at the xe268h and one of the few times i was able to get a hold of comp cams on the phone they recommended it as well but i hear so many times that it is bad about wiping lobes on break in.

not sure i want to risk it.

 

[Rodney Gold]

If you use the right break in procedure , buy top notch lifters and use the comp cams additive every time you change oil - you wont wipe a lobe.
Break in is vital , lube everything with the red lube gloop they supply you when assmebling. Make sure the engine fires at the first try or so and rev up immediately to 2500 and vary the rpm from 2-4000 rpm over the next 15 minutes . I use diesel engine oil (rotella) in my motors these days. I have never lost a cam when I have used the comp cams additve and this break in routine.
As an aside , one day at drags I saw a real shadetree mechanic doing a trackside cam change , he was grinding the convex tops of his lifters flat by rubbing em on concrete as he was exclaiming "these damn yanks , cant they make a proper lifter" , needless to say , the car spluttered and farted down the track which just went to reinforce his idea that the "yank" cam was rubbish.

 

[baxsom]

If you use the right break in procedure , buy top notch lifters and use the comp cams additive every time you change oil - you wont wipe a lobe.
Break in is vital , lube everything with the red lube gloop they supply you when assmebling. Make sure the engine fires at the first try or so and rev up immediately to 2500 and vary the rpm from 2-4000 rpm over the next 15 minutes . I use diesel engine oil (rotella) in my motors these days. I have never lost a cam when I have used the comp cams additve and this break in routine.
As an aside , one day at drags I saw a real shadetree mechanic doing a trackside cam change , he was grinding the convex tops of his lifters flat by rubbing em on concrete as he was exclaiming "these damn yanks , cant they make a proper lifter" , needless to say , the car spluttered and farted down the track which just went to reinforce his idea that the "yank" cam was rubbish.

to be fair, i installed an XE256H in my old mustang, used rotella with comp cams break in lube. i installed the spring and lfiter kit that came with the cam, fired to 2500 for 20 mins (open headers good times)

and it is running great 3 years later. if i wouldnt have read here about the xe lines wiping lobes i would have never even thought about it.

 

[Ed's 1970]

I would go with a hydraulic roller, that way u don't ever have to worry about breaking it. The lifters get a little expensive, but sometimes there are good deals to be had on ebay. I have seen hydraulic roller kits go for around $500 at times. The lifters u need have the link bar connecting them together. You will also need a strong timing cover which will hold a cam button. The cam button prevents the cam from moving in and out of the block. It has to be set just right, comp cams makes a cover designed for this, but it ain't cheap. If u do decide to go with a roller, make sure to change your valve springs out too. It's a chore with the heads already on the engine.

 

[baxsom]

ok gonna bring this thread back since id really want to hear from actual users of any of these cams in a BB


of the three i am looking at
the xe268h
the high energy 268h
and the magnum 270h

does anyone have one of these cams in there basically stock 454.
my main goal is low end improvement.
the only real mods are headers and 2500 stall

 

[Rodney Gold]

I use the 268h in a 454 , its in an El Camino - not the USA one , the aussie one , basically a Holden ute - it weighs in at about 1560kgs
I had a much more radical cam in it , a 280+.
Heres the rub - I took the rear end from a 3.75 :1 to a 3:1 , Took off the airgap manifold and the 800cfm Edelbrock and used the stock manifold and a 750holley and installed the milder cam , stock rect port heads and stock comp ratio .. I went from a 12.7 to a 12.75 with the detuning and found the car a lot better to drive on the street.
The cam swap , with a stock th400 , did NOT give me the bottom end huge boost in grunt that I expected , it was better at low rpm but not a night and day difference. The vehicle has very little traction as is , i use 295/50/15's out back but it has a leaf spring suspension (I use a ford 9") and this "worsened" to the point the vehicle cannot be used when the roads are wet and turning a sharp corner in 1st or 2nd doesnt need much to provoke a 360 or "unassisted" turning.
You have a high stall and high rear gears - the extra torque of the lesser cam will make your stall higher...but the high gearing and limited revving of the milder cam will limit your top end.
Assuming you using a 235/50/15 out back , your gearing will be 32 k/per 1000 (20m/per 1000) and your top end would be 186 k's or round 115mph at lets say 5700
You might want , with this setup , a cam that can rev to 6500 or so and to limit your bottom end , cos the stall will "take up slack" so to speak ?

Any cam you listed will "work" with what you got , even something more radical will , unless you match up a more radical cam with a low comp engine , and you arent sure of what your comp ratio is , so assume its under 10:1....
So my advice right now is to select a cam that works with a 9.5:1 comp engine , I cant see any of your listed cams being hugely superior to each other....
My take on your situation would be to up comp ratio to 10:1 and then use a radical cam as you seem to have the rest of the equipment to utilise it.......I'm not quite sure why you want bottom end with those rear gears and the stall...?