help with newer top end combo

[Project86]

So I recently pulled my current combo out for all new deals and gaskets.
It's a .40 over 350. With a Xe268 cam. 993 heads stock performer intake and a Holley 650
I've had this big cam sitting for a pretty good while.

It's the 305h Magnus cam and lifter set.

I have a friend of mine that has some ported/polished a d worked heads. 882s I believe. They were on a 11.5-1 roller motor. Guide plates screw in studs etc.

I'm thinking of throwing in this 305h cam. Getting a Victor jr intake using his worked up heads. And installing a 3000 stall in my built th350

Is this a bad combination? My CR i would venture out to say is around 9.5-1.

I know it's pretty much a bracket racing cam.
But would it be ok for a limited street use truck?

[Domer]

Everybody has a different opinion on what is street able. I'm running a k1109 which is a similar cam. But I have a 6-71 blower, and world sportsmen 2 heads, th350, 2500 stall, and it was street able. I was told it would be completely unstreetable but with a 4 letter word. I drove it all the time. And this was in a bagged and body dropped truck with 3:08 gears.. Cruised it all the time. Now it wasn't super snappy off the line.. I could have used a higher stall, but I didn't have any problems.
Cam specs
Adv - 312/322*
@ .050 254/264*
Lift - .537/.559
LSA - 114*
1.5 Rockers

[Captainfab]

The Comp 305H Magnum is a pretty big cam. Most don't consider a 292H Magnum streetable. You are going to need more than 9.5:1 compression with that cam. As just a guess I'm going to say you will need 10.5 to 11.0:1 static compression. The dynamic compression will need to be calculated with the 305H Magnum cam. A 3000 stall may not be enough.

[Super73]

I personally would try your current cam with the heads before sticking a 25x degree @.050 in a 9.5cr 350. Will it run and drive, sure.. Will it move a 3800lb+ truck very well? Probably not.

[Marv D]

At the risk of sounding like a smart@$$,, the cam is fine,, it's the heads that are all wrong.

Home ported heads can be OK or they can be a totaly screwed up POS ,, or if the guy that got an air grinder and a bag of tootsie-rolls for Christmas was lucky,,, and experienced, and had a flow bench,,... they can be OK to decent. But they're never going to be a Bowtie,, or Track-1 or AFR or Brodie STS. I've had a few sets of production castings that were ported by guys that 'supposedly' knew what they were doing,,,, I learned if that guy didn't have a flow bench,, or a CNC machine to repeat a KNOWN improvement,, They likely made a mess.

Not saying that's what you have,, just saying before I invested a bunch of hard earned cash in the heads, or in a cam to go with these heads,,, I'd have them on a reputable flow bench to see what was done.

[KQQL IT]

I ran a 292H in my 406, it was ok.
The 292H with the short 400 rod was a better combo.

[Project86]

As soon as I get home I'm taking the heads to a local speed shop to have them checked out.

They came off a roller motor and my buddy has all the valvetrain ready to go.

I may see what CC they are. and I may talk them to see if I can have them shaved down to bump up compression. And just go with a different roller cam. Checking PTV clearances as well.
But I do know I have 4 valve relief pistons. So I will have to see.

[djracer]

A hyd roller would be best for the street unless you don't mind adjusting Valves fairly often.

[Project86]

I want to say its hydraulic roller. Not certain but I will check

[PGSigns]

What ever you decide to do for a cam change the springs to a set matched for the cam shaft. Don't make any assumptions on the springs. You will need to know a lot more about your short block to figure out what to do with the heads. At the minimum the part number on the piston and the measurement of how far down in the hole they are. With that info and the CC's of the heads you can see what you have and if you can get where you want to go. If you decide to angle mill the heads to get the compression up you will need to also do the intake. Then these two stay together for ever. Then I would look at getting the heads flowed and picking a cam to work with what you have for heads. All this adds up quick to make what seems like a good deal work and can easily run more than a good set of new heads.
Jimmy

[Project86]

Originally Posted by PGSigns

What ever you decide to do for a cam change the springs to a set matched for the cam shaft. Don't make any assumptions on the springs. You will need to know a lot more about your short block to figure out what to do with the heads. At the minimum the part number on the piston and the measurement of how far down in the hole they are. With that info and the CC's of the heads you can see what you have and if you can get where you want to go. If you decide to angle mill the heads to get the compression up you will need to also do the intake. Then these two stay together for ever. Then I would look at getting the heads flowed and picking a cam to work with what you have for heads. All this adds up quick to make what seems like a good deal work and can easily run more than a good set of new heads.
Jimmy

All very good info and advice as well j is a 4mmy!
I'm still weighing my options. I work offshore so I have a little bit of time. I may just end up revealing what I already have and just wait until I'm certain of what I want. I do know my block is a 4bolt main 350. Bored .40 over with mahle 4 valve relief pistons. Just oversized replacements. Stock crank stock rods. I will probably end up taking my block and those heads and seeing what the combination will most likely come out to be. If it works in my favor then I'll go with that. However if it ends up being more money invested than expected. I will just wait to convert it to a roller motor and aluminum heads and high compression

[hotrod 80]

Probably not a popular suggestion , but if it were my truck/combo I would add a set of vortecs and an intake to it . Better flow and tighter chamber for more compression .

[Bad70sbchevy]

I'm running 882 heads on mine with 2.02 valves with a 292H cam with a single plane intake and I've been daily driving it for 6 years before I couldn't afford the gas and I've been really pleased with it, just my 2 cents.