question on 289 performance upgrades.

[jhop1]

Right now I have a 289 thats .60 over, with weiand stealth intake, edelbrock 600cfm carb, ford tri-y's, dual flowmaster 40 series with H pipe, elgin cam which is .496 lift forgot the other specs but its pretty mild it seems. 3.55 gears, 2000 stall converter.

right now the engine makes about 260hp and 280tq

I was wondering If i got a set of GT40 heads and ported and polished them and increased the valve size, Got a custom ground comp cams camshaft close to .541 lift, and new rocker arms. how much power would it increase. also my powerband now is from idle to 5500rpm, but my intake can go from idle to 6800 so the new cam is going to be ground to be from like 2000 to 6500rpm. Those 2 parts should increase the power quite a bit right? im also going to add an edelbrock 100shot of nos to top that off.

Let me know what you guys think about the cam and heads.

 

[66mustanger]

Youll blow it up!

Youll blow it up man!!! Are you insane! No, now it depends on what kind of pistons that youll be running. I dont think that you stated if your rebuilding the motor or not, but watch the lift with the cam and the size of valves that youll be running! You might have to watch for floating the valves and smacking the top of the piston!

 

[taylor4g63]

with that much lift your probably going to do some notching on the pistons. I got lucky and didn't have to do any notching, but i definitly cut it close (specs in sig) Also if the valve sizes get over 1.94 then they MUST be notched.

If you plan on running over 6000 or so rpm, i would plan on putting some roller valve train in there, and i wouldn't trust stock rods too much over 6000rpm too often either. It would be a nice combo tho, I've got something very similair, pulls VERY hard. The heads i am running have slightly better flow numbers than stock gt40's, so i imagine with those heads u plan on getting it'll haul ass.

Just ani dea for you, with the kinda money ur going to dump into those gt40's, you could probably pick up a decent set of used aluminums. Just a thought for ya.

 

[Ghxst]

My godfather used to build 302's for his race car using 289 internals. With the STOCK rods, he would turn those motors at 8000rpm's all summer long. One motor that ran really well lasted 2 summers. So, what I am trying to say is the stock rods are fine but of course aftermarket ones are better.

 

[fastcoupe68]

put arp rod bolts in those rods and you just increased your reliability 2 fold. I personally ran the stock rods with ARP rod bolts and twisted that motor to 8200 rpms alot. Never had a problem.

 

[taylor4g63]

Wow, learn something new everyday. I've always heard of people having problems with rods if u reved to 6500 alot. Guess that was another type of motor tho.