help with top end combo
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Joined: Sep 2008
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From: Long Island, NY
help with top end combo so my uncles has a 454 73 nova that is bored .30 over. is combo was made in the late 80s and is old technology. he is looking for a mid 11 sec car. right now the car has a 12 bolt with 373s and weighs in at 3200lbs and a 3 speed auto. he also has 11-1 dome pistons so he has to watch out with PTV clearance. what do you guys recommend?
Launching!
Joined: Oct 2006
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What heads are on it now? Mid 11's in a 1973 Nova with a big block should be no problem. I would think a set of early oval port heads with bigger valves and a little port work, a solid flat tappet cam with 240'ish duration, RPM Air Gap and an 850 double pumper should do the trick. Pump gas with 11:1 and iron heads isn't going to work out too well. Does he run race gas only and no street time? For this build, I would definitely stay away from rectangular port heads.
What heads are on it now? Mid 11's in a 1973 Nova with a big block should be no problem. I would think a set of early oval port heads with bigger valves and a little port work, a solid flat tappet cam with 240'ish duration, RPM Air Gap and an 850 double pumper should do the trick. Pump gas with 11:1 and iron heads isn't going to work out too well. Does he run race gas only and no street time? For this build, I would definitely stay away from rectangular port heads.
Launching!
Joined: Oct 2006
Posts: 289
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I would stay away from the rectangular ports because they just aren't needed. He will be giving up useable torque. I am new to the BBC, but when I built my 496 I did a lot of reading and asking questions on the chevelles.com forum (lots of big block builders over there). There are guys making HUGE power with oval port heads. I put a mildly ported set on my low RPM 496. I am shooting for 500HP/600TQ and a 5800RPM shift point. I did screw up the compression. I ended up around 11.5:1 because the 049 heads came out at 109CC chambers instead of the 120ish I was planning on. The heads were milled and I wasn't aware of that.
Yeah I guess you have a rather good point. Most of the cars that I was refering to in the 60s and 70s were stick shift cars with big gears. So the torque loss was no big deal. Dr. J's Performance ported a set of oval ports for a 496 that was featured in Engine Masters Magazine a couple years back that made right at 700hp. That was a real big deal too. But those guys are top notch. A set of blended square ports would do okay also if they were readily available I would think.
