unknown_host

iTrader: (1)

I want to copy Car Craft's recent 440 horsepower 450 torque 350. Its specs are as follows:
10:1, Vortec Heads, 350 block, comp XE274 cam, Performer RPM Air Gap intake, 1.6 rr's, Edelbrock 750 carb.

I have a 350HO with vortec heads and 9.1:1. I want to copy this buildup exactly, so I was thinking of having my heads shaved and prepped to take springs that will withstand the amount of lift that the 274 will have. Who here has experience shaving vortecs, good or bad? Also I was thinking about having some mild work done to the heads is this a guy idea as well? Thanks.

toosloz

i am doing the vortec swap....same cam and ill be about 9:6:1 with the 64 cc chambers...can't wait


and btw.....wheeler motorsports sells vortecs for 600 new with .550 lift springs and comp cams springs, retainers and locks....the guy said they would shave them down to 58cc

86 sc

how do i get a hold of wheeler do they have a web site? do you know if they have any 400 short blocks?

johnsjj2

This is a little off topic, and I hope I don't start a war, but when these heads came out, I would have never thought they would support 440hp. I was praying for 400 when I built mine. THat is why I ported them, raised the CR, and installed a bigger cam. I am now more anxious to get some 116 fuel and get my timing in line to where it should be.

Jer82Z28

personally I wouldn't bother trying to get that extra .9:1 compression. you wont gain much hp and it's more work than it's worth.
With less compression the engine will be waay more streetable.
thats my opinion.

I didn't think these heads were able to make hp past 400 either, but there's guys on this board in the 12's with their vortec engines.

and here I'm stuck in the high 13's

unknown_host

iTrader: (1)

I was worried about the compression because a lot of times decent sized cams depend on having a certain amout of compression to actually start adding performance and what not. these heads are based off of corvette heads i guess. i think they are cool but maybe overrated. i would take aluminum heads over them anyday of the week.

Pony Killer

That's a VERY similar motor to what's in my Z28.

The differences to that motor and mine are such.
them ................................. me
10:1 comp........................... 10.65
rpm airgap...........................rpm with spacer
1.6rr's..................................1.5 race golds.
stock heads.......................... not stock heads


you may run into a few glitches.... the xe274 cam is a hydraulic grind, not a hyd roller. if you chang you will need MUCH lighter springs in the heads..

Don't let anyone fool you about compression ratio, it's the only engine componenty that's got a direct relation to HP. Bigger cams need more compression to keep cyl pressures up since the "bleed" off some compression with the overlap.

The best way to bump higher compression is to run flattop pistons and deck the block, you want to leave the combustion chamber shape close to the same


I'm running Flattops with 2 valv reliefs like 4-6cc i cant' remember
a posative deck hieght on the pistons, and 62cc vortecs.

Bottom line with a cam like that you want the higher compression but you dont' wanna mill the crap out of the heads to get it. if you can't get it without putting the motor apart.. run either a roller version of the 268 cam, or run the 274 with lower compression

unknown_host

iTrader: (1)

Ok so say i have the vortecs taken down to 62 cc and get thin head gaskets will i be around 9.5 if i am currently at 9.1 with 64cc chambers?

johnsjj2

Have you had the chambers checked for your actual cc? Numerous magazines, and people on here even, have found that most of these Vortec chambers are closer to 62cc. I agree with Pony Killer, try and keep the quinch area as flat as possible. If you have a big dome sticking up into the chamber, the flame travel will suck real bad. And the combustion force pushing down on the piston will be greater in some areas of the piston top than others. I am running a little over 11:1 CR, with the XE282 Roller. In my opinion, this setup runs excellent. I love the power it has. I have debated going to a slightly smaller hydraulic, non-roller cam, but after sinking $250 in the one I have, I don't want to find that my efforts were in vain!!

Pony Killer

yeah it's been a long time since i dicked with the heads on it. If i remember the only thing done to the decks were just a few thousanths just to make it utterly flat.

unfortunatly host, the best way to drive the compression up is to run true flattops and a lower deck height.


Here's the thing, if you run a thinner head gasket you better make sure both decks, block and heads are level, cause they aren't as forgiving. in which case you'll be sending the block out.

If you want to run that cam and those heads replace the springs, leave the shortblock alone.. the XE cams don't require anymore than 8:1 compression according to comp. in which case you don't need any more than you have.

if you put a set of vortecs with 62cc chambers on it, the compression will go up marginally. run a good thick gasket. and don't worry about it..

The difference in hp between 9.1:1 compression, and 9.3:1 compression is like 4hp not a lot to worry about