$6500 won't get the boat out of the driveway.

If he can spend the 8k he was going to spend, plus the labor, plus sell the 496 HO for say 6k and add another $6500 he'll have what he needs. 700 reliable and quality HP costs 23k bottom line.

Raylar shortblock is $6500. The 600HO kit is $13K. I have two of them for 7 years and have 250 hours on them. They are pretty much maintenance free fuel injected motors that dyno at about 640HP

Anyone have any experience with these options from ATECO listed in the classifieds? I personally like the turnkey reliability of my 496's and plan to leave them as is, but these upgrades seem like an interesting alternative for those looking to upgrade.

https://www.offshoreonly.com/classif...96-o79136.html

https://www.offshoreonly.com/classif...96-o79135.html

My opinion, but I am a Raylar fanboy...
If he does DART heads maybe...
The 500HP isnt worth it IMHO
The 600HP still think you can get more out of the Raylar. Heres why, the heads. Looks like he is probably running the stock heads with a CNC job on the heads for the 8.1/Gen 7 HP3. (This was a 525 horsepower variant for the 496/8.1) The stock heads are dog crap. I did the CNC program on my stock iron heads 8 years ago. The jackets have about 1/8 or sometimes 1/16 of material left. Then dropped a valve in one and the other cracked.

Raylars package is vanilla, you can get the rockers and port your own intake and get close to his cool gap. The cams are pretty good, the 600HP cam is basically a tad hotter 731 which has proven itself for 20 years. Whats special is the aluminum heads, yes you can do the DART 496 heads in iron, but after you do the valves you would still have to do a little port work to get it close to the Raylar heads and the new Raylar ported heads are off the map good. Reher Morrison designed the heads and did a really good job. 8 years ago when I got mine I took them to 3 well known shops to port them and 2 of the 3 gave them back and said they flow great dont fk with them. The 3rd guy bench ported and flowed them but admittedly couldnt do too much.

No experience with the above packages. I'll buy the 500hp setup but call BS on the 600hp package. GM tried on the Gen 2 HP3 496 and got to about 560hp on Valako ported stock heads with big valves. Ateco does not even mention what intake is being used.

I agree with Keith, stick with Raylar. Proven parts and packages. Great customer service as well. Larry is always a phone call away for customers that buy his parts. Hard to find nowadays.

I agree with going Raylar. Larry's parts are top notch and the support is great. Even when my machinist called him he spent about 45 min on the phone with him.

I am thinking about doing a gradual upgrade on my 496 MagHo with 130 hours. I have been following Ryan00TJ's and Keith's upgrade and they have been very informative. Has anyone upgraded just the iron heads with the Raylar aluminum heads on a 496 MagHO but using the stock factory push rods, rocker arms from the stock heads?
Any idea of the approximate horsepower increase one can potentially gain by going that route?

I've read a few times it being said the heads alone are worth about 65hp on a naturally aspirated engine. Keep in mind though, the real restriction or weak point of a stock 496 is the intake can't flow enough. So, I can't say if you would really get that much gain with just heads.

Sorry to butt in but is Jim Valako still around? He was in Grand Rapids last I talked to him.

I don't believe many have gone just the "heads" route. The stock intake then becomes the restriction. Baby stock cam does not take advantage of the new heads. The smaller cc of the Raylar heads will put you around 10-1 scr.

Old post by Raylar when they were dyno testing their new heads in 04' stated......... 496HO with just our heads and a slight fuel pressure increase made 478HP @4800rpm and 536ft/lbs torque at 3500rpm