Greetings from down under

guys, I come to this great site, the mecca for chev enthusiasts, seeking knowledge and advice

it probably is the oldest argument, but i'd like some specific advice on my donkey, the question is to blow or not to blow.

I'll cut to the guts.....

I have a 70 camaro, 454 with tremac 5spd and 3.36's at the rear, old owners say around 45ohp at the motor which i guess sounds right. At the bottom of this email I will copy n paste the engine specs.

The car is a once a weekend driver used to horrify the neighbours and generally cruise, but nust wake up and scream when asked nicely.

I would like to 'grab' another 100hp and am unsure whether to get this with a low boost supercharger or ny working with what i have, so i ask for learned opinion, based upon the engine specs at the base of this email, on the following 3 suggestions. I do have a budget, but its more set around the horsepower requirement rather than the *** - just the cheapest way to acheive another reliable, streetable, 100hp.

1, option 1. quite simply bolt on a centrifugal charger and grab the power that way

2. aluminum heads, demon 850, new slugs to raise compression from current stock 8.75 ( or thereabouts ) to 10:1

3. ( budget version of number 2 ) port and tweak current iron heads, demon 850, and new set of pistons as above

If you believe I am on the wrong track with my thoughts, then all suggestions, apart from buying a Ford, are welcome

current specs following

*****************


1, 2 bolt maih
2. demon 750
3. iron heads
4. stock bottom end, rods, and slugs
5. headers


Block #14015445
Heads #3856206 G28-5 (manufactured Aug. 28 1975)
VIN#: 124870L510964
Cowl Tag: ST-7014487-8L10-326PD

Bore: 4.25
CID: 454
Torque: 510
CAM: Crane Fireball cc 3142 with Solid Lifters & Roller Rockers
314 248 .567 110
324 258 .590
Lash: Int .018  Exh ..020


Kind regards


Simon  

Could you get the compression up with the right sized combustion chamber. A set of good flowing aluminum heads with a smaller chamber and roller cam would most likely get you your 100 hp. I would keep the 750 for a street car. The Demons I have seen tend to run rich at part throttle, how do your plugs look.  

Schum:
Could you get the compression up with the right sized combustion chamber. A set of good flowing aluminum heads with a smaller chamber and roller cam would most likely get you your 100 hp. I would keep the 750 for a street car. The Demons I have seen tend to run rich at part throttle, how do your plugs look.

clean, no issues that i can tell, and seemd alright for the current demands, but i had been anticipating it may have been a bit light when heads are opened up  

Your current heads have closed chamber at 97cc or so.100 more hp I believe could be had with Trickflow or Dart Pro 1 heads and a single pattern cam which is best for these heads.The reason why is that they have raised exhaust ports and don't need extra duration on the exhaust lobes.Do you have flat top pistons or some size of a dome? What's your piston to deck clearance also.Head gaskets play a role too.A more current technolgy cam will help with hp,like a CompCam Xtreme solid with 236 int and exh don't be fooled by the smaller duration I have a custom Xtreme with 230 in a 427 and pulls hard to 5800 and raised exhaust iron oval Merlins.Your short block like mine is rpm limited at around 6000rpm.Get the solid lifters with the laser orfice on lifter face and Beehive springs. WIEDER  

The closed chambers heads are very restrictive and inefficient. Even if your current heads have large valves installed the severe valve shrouding is most likely going to inhibit the effective flow in and out of the engine. There's a reason why GM phased out all closed chamber heads and didn't return to them for 25 years.

I second the the vote of the others here when I ask why mess with a blower when you can easily achieve your goal naturally aspirated. The only way I can see going for the supercharger is if you're worried about the 'validity' of your horsepower estimates. Supercharging is a more definite way of arriving at your horsepower goal but using better cylinder heads would probably be just as capable (to a certain extent). Of course dyno-testing would completely eliminate the guessing game...  

my preference is to do it au natural, without the charger. thanjks for the advice so far, pretty much confirms my suspicions

how limited am i by the fact its a 2 bolter? am i ok up to mid 500 hp? also, what compression will be 'safe' and would i best achiene this with new slugs, or a new head, or preferably both ( slugs at the moment are complete stock )

thanks

Simon  

Crank and rods and block will survive if they had good machine work,do you have ARP type fasteners on your main caps and rod bolts?Forged pistons are in order for your hp goal which I should have stated on previous post.BBC two bolt blocks if prepared right can handle your projected power level with reliability.Like GibTG said craming bigger valves in those closed chambers would hurt power.I also should have mentioned that I recommend oval heads. WIEDER  

Thanks Wieder - afterthe above I certainly won't be wasting anytime on these heads and they will be destined for the storeroom! Is there any online comparisons you know of where they have tested BB aluminium heads against each other  

It was 1 or 2 chp issues back I believe,can't remember the title of the article because I think my issue sneaked out and jumped in the recycler can't find. Tested Edelbrock,Trickflow,Brodiox and Dart Pro 1 ovals,sure miss that issue.    WIEDER  

Yeah, the best route I'd recommend is a cam and head swap. Get the compression up around 10:1, and a healthy hydraulic roller cam will do the trick nicely. The Demon 750 should still handle that alright, so I wouldn't go to an 850 cfm carb.  

Welcome and i hope you find what your looking for!