Its finally time to change the motor in my WH caprice. I have another ls1 block which im going to rebuild and drop in. At the moment i have done the bolt ons...
1 3/4" pacemaker ceramic coated headers
hi flow pacemaker cats
2.5" red back cat back
VCM OTRCAI
currently makes 270rwhp

The motor to replace im wanting to build is about 500hp (~420rwhp). I know the caprice is a boat so its not going down a drag strip. Its going to be a cruiser which will be more aggressive. Im curious to see what build people have to achieve this power or something similar.

If this post has already been done please delete

 

Don't be too sure about it not going down the drag strip, a mate of mine has one with a Comp off the shelf cam, around 238/240 at .050"and .600" lift, I think it's an XER287HR, look on Comp's website. It has mildly ported 853 heads, fairly standard compression as far as I know, an LS6 intake, OTR, Aus throttle body or something like that, some 4 into 1 extractors (not big diameter tubes) and 2.5" twin exhaust.

It has a 3800RPM converter, 3.9 - 1 diff gears and weighs about 4000lbs. It just made around 390 - 395 RWHP at High Torque and on the weekend with not the best conditions ran 11.96 at 115mph at Willowbank with ET street radials and he's not a super aggressive driver. Better conditions should hopefully see an 80 or maybe even a 70 at possibly 116mph. It's done an 80 with the previous owner and would be making a bit more power now since he's freshened it up and had the heads played with so an 11.7 is entirely possible in good conditions.

I've been in it once and it's an incredibly well behaved car with all the luxury items but sink the boot in and look out. It does have a pretty serious lump at idle and a bit of valve train noise but you can't really hear it too much with the windows up. On the highway the converter locks up and it's like a stocky.

I ran into his wife taking one of their kids to school in it about a month or so ago when her car was unavailable so that's how tractable it is. It's a really impressive car that you could easily drive everywhere if you wanted to, I'm not sure how the fuel economy is though, I hope this info helps you.

Best wishes,

Jason.

 

Any basic heads and cam package will get you there. Check out some of the sponsors and vendors on the site for choices and prices. Lots to choose from

 

Get some 243 heads milled down .020 or so, bigger injectors to keep up with a good cam and you're there. I was at 434 RWHP with that and a FlowTech Induction StreetSweeper HT cam. Very streetable cam with lots of low end grunt

 

Cheers Jason, that actually helps a lot. Thats a simila set up to what im looking at. Its good to see that it can be used as a daily still as well as having all the power under the hood. If it ever got <12s on the quarter i would be pleased. Looks like now ill be looking at parts to put together and go to my mechanic to get it built.

Thanks again for the info

 

Thanks for the info. i know im targeting a 500hp motor so i need to spec the parts around that. The cam will be the defining choice i think, it still needs to have bottom end whilst maintaining an aggressive idle. Ill keep looking around and asking questions! cheers guys

 

G'day Beast,

Just a follow up, tonight in much better conditions the mate managed an 11.85 at 116mph. He had the tuner set the shift points at a conservative 6700 RPM but it still makes power up to 7000 so there's probably a bit more in it if he wanted to rev it a bit harder. We tried to shame him into shifting it manually at 7000 but he was having none of it, he doesn't want a race car so he's happy to rev it less and help it live.

For your info as well, although his car could be driven daily with ease, there's better qualified people on here than myself who'll tell you that XER Comp lobe profiles are pretty aggressive so if you were to use that cam like his and daily drive it, a well set up valve train will be very important and be prepared to keep a reasonably keen eye on your valve springs.

Your goal is pretty conservative by some of the standards on this site, depending on your budget and how you want to drive the car, you may be well served looking for a better cylinder head and a less aggressive camshaft to achieve it.

Good luck with your build, keep us posted.

Best wishes,

Jason.

 

Hi Jason,

Thats an impressive time and to still have some power in reserve to. He must be rapped with that. My plan is to do a full rebuild on the motor. So its going to be stripped right back to a bare block and build it up. I dont want to spend every last dollar i have on it but i do want to do it properly.

i read that the lobe and overlap is what determines how aggressive it will sound, but at the cost of bottom end in some cases. Im gonna base my setup on what you have told me i think. Unless i decide to stroke out the motor. I still am not sure on what parts to use. ill be talking to my mechanic this week who has built me a motor before and love it. ill update shortly.

Cheers,
Nick

 

This for sure! 500hp is really easy to make just make sure everything lines up and you will be fine.