Hemi2Slo

OK folks, here's a cam design idea that I'd like some opinions on. I'm building an LS1 for my truck to replace the tired 5.3. Now, before anybody asks why, I have the LS1 short block and a set of 243 heads laying around gathering dust, so why not put it to use I figure. Freshening it up and assembling it will be cheaper than buying a 6.0 and doing the same to it, so here goes. Its going in a single cab, 2wd, short bed 2004. 4l60 tranny with a 03-04 trailblazer torque converter. The 243 heads will have a mild hand port job done to them by a friend, not the best option I know, but its free and he did a good job on a previous set for me. I'm leaving the heads uncut and staying with the stock pistons, so figure around 10.5 compression. Stock 04 truck intake will be used along with cold air and long tubes.

So, background laid, here is the question. The truck will be used as a daily driver and will also be towing a 3500 lb. boat several times a month. I also want it to be a decent drag racer. That said, I figure that somewhere around a 215/220, 112+4 lsa cam will do good for the towing part, but I figure it will probably run out around 5500 rpms, or at least, stop pulling harder around there. So I had the idea of doing something like a 220/224, 112+5 lsa cam. I was thinking that the slightly higher duration can feed it up top, but the 5 degrees advance will give the low end I need to tow. Kinda split the difference. What do you folks think? I appreciate the opinions in advance.

Mark Johnson

iTrader: (1)

The first profile. What kind of lift ya planning on as that will tell you where in the lift cycle you spend most of your time............

Hemi2Slo

Around the .590-.600 range. Not over 6 for sure. The current cam I have in the 5.3 is .596/.581 and it seems to like it so I will stay around there, plus everything I've read and experienced seems to agree that 243 heads like to be around .600.

turboal1

218/220 would be better, 243 heads have pretty equal flowing ports
don't need a lot of split dur on cam, large splits seem to hurt 243
headed motors.

JohnDaMan

iTrader: (7)

I get about 10.6 SCR on my calc for your setup.

Speed INC sells a 'TBSS torque cam' (214/220 111.5 LSA) that has specs pretty similar to your first theoretical cam. With the 10.6 SCR and a TBSS torque cam you would be right at 8.58 DCR with a stock head gasket. I figure the Speed INC cam has +2 advance. Should be a real responsive combo with a lot of torque.

madmann26

iTrader: (7)

I run a COMP LSR 265 cam. I love it and it pulls great with 4.11's. A lot of the "feel" of the truck will come from a solid tune.

Hemi2Slo

Thanks for the ideas folks. I'm going to talk to Cam Motion on it too, he's made several cams for me and has always been spot on, but I figure he'll say about what you guys have said. Tune isn't an issue as I tune myself so I can just keep tweaking on it if I don't like it. I do like the idea of the 218/220 but I'm just wondering if it will tow as well as I want it to. I also like 111.5 LSA, they sound great, but have always hurt mileage for me.