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Author Topic:   Engine questions
Builder
Member
posted June 06, 2004 07:42 PM
I have built my first pure stock car 77' camaro. I bought a 400 that was supposed to be in good shape put it in the car and fired it up. it sounded great at idle gave a little throttle it started knocking. with 4 days before dace day i pulled it and found a
stock 350 it came out of 78 Impala it had low miles and sounded good so i bought it.
i changed the intake over from a 2 barrel to a 4 barrel bolted on a quadajet and went racing.
It took a couple weeks to get the car set up to handle good so i was not real worried about my lack of hp. now the car handles just how i want it to.

I am running a 350 turbo tranny in 2nd gear
my rear end gears are 273s i am running on a 1/4 tacky clay track good banking. the cars dose well thru the turns but i am getting beat bad out of the turns and on the straights.

So far the best i can come up with for info on the stock 350 is 10-1 comp. approx 185hp
what can i do to get more hp out of this engine and still stay under the 12in vacume rule. i am now pulling 18in of vacume @1000rpm

I am thinking about changing the cam but it is alittle confusing tring to figure out with one to go with. i also have a very small budget at this time because for some reason i spent more building it than planned
any suggestions would be very much apprieated
Thanks
Tom martin
04 pure stock


racer17j
Member
posted June 06, 2004 08:27 PM
your going to bemore like 8.something 1 on a bone stock motor with 76cc heads on it you'd have to get some 305 heads and flat top pistons to get up to 10;1. a cam change is definaly in order i have never delt with a vacume rule tho so can't help you there but try a search on here i'm sure you can find a bunch of posts on vac rules


Raz_900
Member
posted June 06, 2004 08:38 PM
Ya, a stock '78 motor will probably have 882 heads on it and around 8:1 compression... 8.5 at best. No way in the world a stock '78 motor had 10:1.

Depending on your budget, there's alot that could be done to it. Although, if the bottom end is totally stock, I'd upgrade the lower end components before throwing a big cam and better heads at it.

At the least, get ARP main bolts, Clevite or Federal Mogul/Speed-pro rod & main bearins, a set of stock recon'd rods w/arp bolts and a set of Speed-pro flat top claimer pistons and moly rings. With a reground stock crank and balancing, you should be able to put the short block together for around $1000.

Throwing a cam in and trying to rev it past 5500 is just going to blow the thing apart in very short order. With 8:1 compression, what you'd gain in top end you'll lose twice as much at low rpm with a bigger cam.

You could also invest in a set of gears, a LW spool and run the tranny in 3rd. That'll save a couple HP compared to running 2nd.

Although, if the 350 runs and you have the 400, I'd spend the money on fixing the bearing/rod knock in the 400. Then you can still race while fixing it right the first time.

waltonjr1
Member
posted June 06, 2004 08:41 PM
You can run a fairly large cam and pull 12 inches. With stock heads and intake I wouldent go much over .480 lift but with that vac rule you could get away with 5teens but it will probally hurt you more than help. The comp 12-325-4 would prob put you at about 15 16 inches and is a real strong cam.



chomme
Member
posted June 07, 2004 09:10 AM
Depending on your rules - compression and the right cam will do wonders - 12" vacuum is quite low for a vacuum rule, so that leaves it pretty open.

What I'd do on the cheap - go to midwest motorsports or other place and pick up a cheap $350 claimer kit. Get a set of large domed pistons (.200 or .250 dome), and one of their milder cams in the .500 lift, 280-290 dur, 108-109 lsa. Just make sure your springs can handle the lift (or get the cheap $39 'z-28' style springs for .550 lift) That should make plenty of power until you get into re-working the heads and installing undercut valves, etc. If the block is in good shape and the heads are too then just de-glaze (light hone) and assemble - keep the RPM's under 6k-6200 RPM and it should live for a long time (got 4 seasons out of one like this - only difference was it had to be bored .030 to clean up the bores)

I've used this combo in pure/street stock classes with good luck and under $400 it's the best bargain for cheap HP

check http://www.midwestmotorsportsinc.com and look for their MWM355KIT - that's the 350 kit. Other places have a similar deal so just use whomever you like (I used them since they were local)

racerss10
Member
posted June 08, 2004 09:45 PM
if your running 350 trans and 2.73s on 1/4 mile you should be in first gear


rico 08
Member
posted June 09, 2004 08:08 AM
The old 350 horse cam works good .224-.224@.050 .465-.480 lift,elgin part #10312...should pull to 6000 and fairly easy on parts.My 10314 elgin pulls 14 inches but i wouldn't recomend it with low compression.


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