360 sbc head decision

[racin69z]

I am putting together a .060 350 for a 71 k5 blazer. It weighs about 4500 pounds and has a granny low 4 speed with 3.08 gears. I like that combo because it cruises down the highway just right. I know this isnt a high level race engine, just another sbc.

The prior combo is going into my sons truck which pushed the oil filter gasket out when it was 7 degrees out the other day. I assume the blocked filter bypass caused that.

Anyway the prior combo was a 9.2:1 355 with vortec heads with oversized head and stem rebuilder valves and a home pocket port. Edelbrock performer intake. Comp hr270 cam 110 lobe center. 6210 or 1850 holley carb depending on my mood. Long tube headers 2.5 exhaust turned down at axle. My only complaint this combo was that in the blazer with no top, it seems gassy especially on deceleration. Ive tried cleaning it up with timing and fueling without much improvement. I also tried running the exhaust out the side but hated the sound. I will say that i think i am hypersensitive to the gassiness now.

I have the bare .060 block, a set of vortec heads with a performer intake and a set of pro action 220cc heads with a performer rpm intake. I also have a comp xfi 268. 218 224 570 565 w 1.6 rockers on a 113 lobe sep. The vortec heads will need a complete redo to accommodate the lift of the cam, the pro actions are ready to go.

I know the 220 heads are too big, but if i up the compression to about 9.75:1 will some of the low speed torque come back? Ive had a ton of small blocks, and none have ever really gotten going until 3000 rpm and ive always got by ok. How much low speed torque will i loose? The granny low will get it going, but if it wont cruise that will suck.

Ive been reading about wider lobe seperation with better flowing heads and was just curious how the big head small cam combo would work. Kind of seems like an ls engine in a way. The l92 heads are huge and they run them on SUVs.

Any insight would be appreciated.

Lynn

[Newold1]

Do you already have your crankshaft and rods? If not put a 383 stroker cast crank, hyper-eutectic pistons budget type kit in and take the compression on pistons to 10.0 to 1 with the Pro-Action 220 heads and a nice hydraulic roller camshaft with about 208 Int. - 212 Exh. duration with lift at about .500" on a 112 LSA and it will use those heads just fine and pull like a bear in that Blazer. Use a Q-jet carb on a Performer. Nice set of 1-3/4" tri-Y headers with a 2-1/2" merge into a 3" collector, Use a nice set of chambered mufflers with a 2" exhaust pipes to the back of the blazer.Use a wide band O2 sensor in the collectors to tune the quadrajet. I did a setup just like this about 15 years ago. Best running fun truck ever! Wish I had not sold that Blazer!

[racin69z]

I do have a crank and rods but no pistons. I have thought about the 383. I had a 383 with pro action iron 180cc heads at 10.2:1 with a crane energizer straight pattern flat tappet hydraulic 216 216 450 450 on a 110. I had some trouble with run on when i shut it off. It cranked 210 psi. But it did have great torque. It was in my 72 chevy k20 that weighed about 800lbs more than the blazer.

[Carnut1]

Built quite a few truck engines and I like the vortec build. I have done the big heads big cam in a truck and it has great mid range but with your dead gears I would stick to smaller heads and cam. The 383 is a great way to go, one of my fav combos was a small roller cam on ported swirl port chevy heads. Guys give those heads a bad name but done right they work great in a truck. New style vortecs are even better but get it done in a different way. GVX had a set of Chinese Vortecs at DV's shop I gave an intake and exhaust a tune up. They were the hardest iron I have ever ground on. 250/180 cfm is not bad for a quicky port job. I am not a fan but for the price point very tough to complain. Thanks, Charlie

[pdq67]

Fwiw, the old '80 Chevy, "round corner", long bed, P/U I had a while back came stock with the 1-piece headed 250" 6-banger, a 3.50 to 1 ratio 1st geared Sag, 3-speed and 2.76 rear end gears in it's truck 12-bolt.

Food for thought is all.

pdq67