SBC Build Questions

[Magna86]

Lookings at options to replace my 76 smogger. I picked up a TBI engine with the machining for a fuel pump and roller cam. If I build it the plan is flat tops/roller cam/different heads. Here's where I'm lost. Yes everyone says vortecs(which I agree to a point) Are there any difference between the Jegs/Summit/Allied Motor Parts ones? This engine came with a regular SBC intake as well so I looked at heads to use with that too. What I'm finding for aluminum ones is there all have 200cc runners which are too much for what I want to build. But then I found cast iron ones but they have 72cc chambers. The truck has a TH350 and 3.07 gears so I'm looking for torque not high rpm HP. An help would be appreciated. Recommendation on cheaper roller cams as well. Since I'm 25yrs too late to find take out for $100 or less

 

[Ricko1966]

Lots bigger bang for the buck out there than Vortecs

Best Small Block Chevy Heads: Dyno Shootout!

A quick test of eight pairs of small block Chevy heads priced at less than $1,000 to find the best small block Chevy heads on a budget.

www.hotrod.com

 

[Magna86]

Sadly looks like the Jegs heads don't exist anymore . Their current ones are 220cc ports and 72cc chambers

 

[Ricko1966]

Sadly looks like the Jegs heads don't exist anymore . Their current ones are 220cc ports and 72cc chambers

Not true I looked earlier tonight.

You must be registered for see images attach

 

[CalSgt]

Vortec heads are a decent bang for the buck, or at least they were 25 years ago when you could order a built pair from a GM dealership for less than any of the HO aftermarket units.

If you don’t already have a set of heads, an aftermarket set that will allow you to keep the stock intake etc. is probably the way to go.

 

[Ricko1966]

The way I look at it it would be pretty easy to end up with 700.00 or more in a rebuilt pair of Vortecs,a manifold,self aligning rockers,and valve covers. To gain 25hp. Or you can spend 1000.00,maybe less with a coupon or a sale have new aluminum heads,use your old rockers,intake,and valve covers and gain 60hp. JMHO

 

[xm20k]

64CC chamber 180 runner 2.02 valves setup for hydro roller in angel or straight plug. Uses gen 1 bolt pattern manifolds.

Pardon Our Interruption

Pardon Our Interruption

 

[xm20k]

They also sell OE roller cams that are basically RV/Towing cams better than stock and under 300 bucks. Just the first two of the 8 or so versions they offer, they get more and more aggressive as you go up the line.

Pardon Our Interruption

Pardon Our Interruption

 

[Magna86]

Well it looks like alittle luck fell into my lap. Found a pair of ready to go 062 vortecs that were never picked up at the machine shop for $350. So.i guess I'm building an engine. I was able to score a complete set of take out gm lifters/spider cage/lifter retainers/bolts/thrust plates for $150 shipped. I have an eye on a Edelbrock Vortec 2116 intake for $175 shipped which allows me to keep my qjet.(Which will get a rebuild/calibration) I'm looking at the summit 8800 cam and want to put 1.6 rockers in for more lift..will the .480 lift be a problem for the pressed in studs? If I don't can I use the rockers from the TBI heads on my core?

 

[Bextreme04]

Well it looks like alittle luck fell into my lap. Found a pair of ready to go 062 vortecs that were never picked up at the machine shop for $350. So.i guess I'm building an engine. I was able to score a complete set of take out gm lifters/spider cage/lifter retainers/bolts/thrust plates for $150 shipped. I have an eye on a Edelbrock Vortec 2116 intake for $175 shipped which allows me to keep my qjet.(Which will get a rebuild/calibration) I'm looking at the summit 8800 cam and want to put 1.6 rockers in for more lift..will the .480 lift be a problem for the pressed in studs? If I don't can I use the rockers from the TBI heads on my core?

The GMT-400 crowd really have good luck and highly recommend the Summit 8800 cam in the trucks and burbs. You should be fine using those vortec heads and the 8800 without needing to do any machining for clearance.
https://www.gmt400.com/threads/summit-8800-cam-upgrade.66438/

I would recommend running the GM LS6 Beehive springs and retainers with that cam and you should have plenty of clearance with a 1.6 rocker.

xc_hide_links_from_guests_guests_error_hide_media

One thing you will need to keep an eye on with that stock 70's 350... you will have quite a poor compression ratio due to possibly dished pistons and the pistons being quite a bit down in the holes. I used a stock 1970 4-bolt main A-body 350 and the pistons were ~0.035" deck height. I had a very hard time finding rebuilder pistons with enough compression height to not make it worse and still ended up having 0.020" taken off the deck to get a decent quench and deck height.

The good news is that you would be going from a 76cc chamber to a 64cc chamber with the vortecs, so you should get close to 9:1 without messing with anything. I would still recommend measuring your deck height when you get the old heads off and run everything through a compression ratio calculator to make sure that you get best results. That would let you choose your head gasket to dial in quench height and compression ratio as needed.

 

[Magna86]

Thanks for the video. The heads were rebuilt with new springs but the gentleman doesn't remember anything about them because the customer supplied them. The roller block engine will be rebuilt with flat tops when I take it in. Right now gathering parts deals for that day.

 

[Bextreme04]

Thanks for the video. The heads were rebuilt with new springs but the gentleman doesn't remember anything about them because the customer supplied them. The roller block engine will be rebuilt with flat tops when I take it in. Right now gathering parts deals for that day.

If you are going to be rebuilding the engine then definitely pay close attention. Rebuilder pistons for SBC are almost exclusively down further in the hole than you would expect. You now have heads, which is a big part of the equation. The next part requires you to know how out of spec the stock block is... it can be a lot. Generally just a generic machine shop will not pay very close attention to these things and will just order you rebuilder "flat top" pistons and send it. I would recommend you do the tear down and measurements yourself, then do some research and parts sourcing on your own to get the desired result. If you will be using this for truck stuff and towing, then you want to keep the dynamic compression down to 8.5:1 or less. With the 8800 cam that will likely restrict static compression to the 9.2-9.5:1 range MAX. Use a good static and dynamic compression calculator and play around with a bunch of different available parts. You will likely need to make some compromises with available pistons, deck height, and head gasket thicknesses. It all matters.

 

[Magna86]

When this upgrade does eventually happen I'm going to rebuild the trans. I happen to have a TCI Saturday Night Special TQ that I can use. Will it be a benefit to use it with the upgraded engine or should I stick with a stock replacement TQ? Right now the plan is the SUM-8800 cam with 1.6 lifters. I dont think I want to go any higher since the goal is TQ while maintaining good vacuum for A/C/brakes.

 

[Craig Nedrow]

Check out Skip white, good stuff good price

Home

Skip White Performance offers high performance engines, short blocks, and accessories with over 30 years of experience. Build your dream engine.

skipwhiteperformance.com

 

[xm20k]

If you just have the deck surfaced (.010) and install flat tops, you'll be in the hole about 15 thou stock bore and stroke and a 4.030 bore gasket with a crush of .039 and a 64cc chamber will be roughly 10:1. May need to go to a piston with an 8-10 CC dish to get down to 9:1.

The 8800 has a wide lobe separation (112) and a hair more than stock duration it might have a bit more chop than stock but not enough to need an aftermarket TC and will still make vacuum.

Choppy cams make TCs try to lunge thru the brakes if not loose enough, but like stated the 8800 is 112 not 107 and does not have a lot of duration.

Example of a 107 or 108 duration with a stock converter.

xc_hide_links_from_guests_guests_error_hide_media