You're talking Holdener's language now..... "BOOST IT!"

 

Thats what the 4.8/5.3 was made for 🤣

 

TexasSpeed 5.3L ported heads are about $1500 with springs and can be sent with a 58cc chamber. But if that's out of the budget have a local shop mill the heads and do a valve job, small expense for the gains. Get that compression up for E85!

Get a big cam and don't be scared to rev it out! When I ran the 236/246 summit cam in a 5.3 I was under 3000lbs with a T56 and its was fun to drive. Taking long sweepers at 8000 RPM sounds great especially with an open 4 barrel throttle body on top of a single plane.

 

We made 426 HP with an L33 using a Howards 222/225 cam/spring combo, long tubes and a gen 4 truck intake on the engine dyno. No other changes. RPM was kept pretty modest, and it was tuned with a microsquirt.

More cam, better heads/intake and some RPM could have easily made another 50 HP.
I can't remember the recipe used for the 450-500 HP 5.3s, but we've done them.
The guys that own the shop even did 600 HP N/A with a 4.8 for a boat.

The problem is, $1200 for PRC heads with a smaller chamber, $1200 for a FAST 102, $600 for cam/springs, plus long tubes and whatever else = $3,000+ for 475-500 HP.
That same amount of money with boost gets you 800-900 HP fairly easily with an L33.

 

Sure it can, but that introduces a plethora of new problems for a road race car. Turbos mean more heat, turbo lag, more complexity and less consistency, not to mention how much the chassis will have to be upgraded to keep an 800-900 HP car under control (suspension, brakes, aero).

 

Road racing a V8 at that power range, the engine is the least of the cost, your going to burn a set of tires a day.. so real quick its a 3000 dollar weekend.
Check local rules, you may not be allowed to run E85.. Which means 4 dollar a gallon fuel will look cheap..
Oh yea,, brakes,, new rotors every couple weekends and pads about every weekend, sometimes twice to stay competitive.
I would not bother with a 5 or 6 speed. Too fragile. Just buy a Jerico 4 speed, gear it to match your engine and go. smaller lighter stronger.

What kind of car? Tub or space frame? and What class?

 

I'm not saying he needs to run 800-900 HP.
A 5.3 kept at a modest ~550 HP with boost can easily be kept cool, with the low RPM grunt needed for road racing. I road raced a twin turbo SN95 mustang ~10 years ago at that power level.