Yesterday a good friend came to me wanting me to build his worn out 351w for his new project. He is wanting over 400hp but some driveability. Shooting for around 450 limited to 6300 rpm. Here what I've got to work with. 1969 351w short block going to punch her out .030 with forged pistons 11.1 comp ratio balanced and a studded bottom end. Having the block decked for better gasket mating and using cleveite 77 bearings. Standard mellings oil pump. The top end I'm using aluminum heads with 185cc intake runners 2.02/1.60 valves and 60cc cambers with comp roller rockers. Aluminum low profile intake like a performer rpm port matched. Quick fuel 750 vac secondary (automatic car) and headman long tube headers. 50k volt hei distributor. So now what I'm wondering on is what would be a good cam for the set up and be able to run pump gas. Some of the parts are new that he has already got so now I've got to try to make it all work together. I'm really leaning towards a voodoo cam with around .520 lift. Do you think that will get me in the ball park or do I need more lift? Wanting to go hydraulic lifter if possible. Any help or thoughts would be great. Thanks.

 

Or am I way out on this one. If so what do I need to change. Is anyone making these numbers with a 3.5" stroke? If so what worked for you?

 

Just running some quick numbers, Comp Cams 280H should get you over the 400HP mark. Comp Cam XE284H might do a little better.

I'll run some more tomorrow and see.

Got a part number on that Voodoo cam?

 

Lunati voodoo .522/.538 268/276 duration. Jegs part #
Lunati638-10350703lk. I was thinking it would have good street manners but would livin up when opened up. But it may be a little small now that I think about it.

 

According to various sources getting 400hp with a "stock" 5.0 bottom end is no big deal so I don't see it being much of a problem on a 11:1 351.

Building 400hp Into A 5.0L Small-Block Engine - Muscle Mustangs & Fast Fords Magazine

Here's a 351 build..
http://www.hotrod.com/techarticles/e...i/viewall.html

 

I know the stock heads won't get there without tons of work or nitrous. The heads I'm looking at are made by kng ( I think). They advertise having better flow than the procomps 200cc due to redesigned ports and they posted the flow chart to prove it. The last set of heads I bought were the world sir Windsor's. They really woke the 5.0 up but I don't think it was making any where near 400hp. But it was fun! I believe with the right cam this set up will surpass 400hp with the stock stroke. I looked at the 351w write up and the one thing that was really helping them was the massive rods they were using and efi. Thanks for the post.

 

That cam with 11:1 will need some serious fuel.

I'll run it, but it should be closer to 400, maybe a hair below. You'll need to come down to 10:1, might need to anyway.

 

Dropping the cr to 10.1 is no problem since I ain't got the pistons yet. I know 11.1 would be at the limit of pump gas but to be able to run on the pump I thought I would need the bigger cam just to keep it from pre detonating? I know 10.1 would be a little more street able with a bigger cam. Honestly I'm looking for a good power across the board so when its taken to the track it will climb rpm like a beast. The car is 3200 pound I think and its getting the 355s swapped for 410s. The guy I'm building it for is wanting to keep it all motor no nitrous. So the 400hp range should keep him happy.

 

That cam shows about 419 peak, the XE284 makes a little more power.

The Lunati is a bit small on their advertised numbers, .050 duration is 227/233, which is more along the lines of a 280ish advertised duration.

 

The stock heads won't get there period, there isn't enough material in them to port them enough to flow the 250+ cfm need to make 400hp. The World heads are well known to be pretty poor flowing, they can be made to work with porting but that destroys any cost savings so you may as well pop for a decent set of heads to begin with. I have done a ton of sims in DesktopDyno over the years and there are tons of combos that will pretty much deliver your goals.. and they are not at all radical in terms of compression or cam. Here is one as an example..



And another that exceeds 400hp, if a cam with a little less duration is substituted the torque curve is raised and flattened at the cost of only a little peak hp.

 

If you don't mind me asking what is the lift/duration of the xe284. Its made by comp right? What do you think would be the best cr for thexe 284 and those heads to make the most power and where in the 400s would it fall? Thank for the advise.

 

Or for that matter what would be the best cam and cr for this set up. I'm open to new ideas.

 

Somehow the program isn't show detonation as a problem. It shows detonation on my builds with the same timing I'm running and I don't get detonation.

Hmm...

Playing with the various cams, the Lunati will have better low RPM torque, better curve, the only place it loses is at peak HP by about 10hp.

Looks like a good choice, a hair shy of 450hp, but a powerful engine. Engine Analyzer Pro shows no real detonation issues and timing around 30-35* across the RPM range, though it hasn't been correct on that in my experience.

Peak tq 443@4500
Peak HP 427@5500

This is running AFR 185cc heads. Cheaper heads won't flow as well, but you've got enough of a buffer in there, should still see 400hp.

What kind of exhaust? I did this assuming 2.5 full duals.

 

240 @ .050 .541 intake
244 @ .050 .544 exhaust

Keeping it streetable, I wouldn't go much hotter than the XE284, keep it below 240 @ .050, I'd probably keep the compression at 10.5 or below.

Conanski, I like that graph comparing the builds. I can only do the current build vs the last build. That is a nice feature.

 

2.5 from the headers back to flowmaster 40s is what he's got now. Its new so I don't see much reason to change it. 10.1 and the ex284. Will the quick fuel 750 be enough to feed it?