vintage-racer

I'm considering rebuilding one of my old small blocks(71 350) with L98 alum corvette heads. I've heard they flow fairly decent for 1.94/1.5 with 58cc ,however I have no preconcieved notions about them being an AFR or Trickflow competitor.Just looking for a decent AFFORDABLE set of alum. heads for a hot little street 350. Anybody using these on older blocks?Do these use a vortec pattern intake or a standard alum intake?

chevygod

I have a ZZ3 motor with those heads. It uses a standard old-school Small Block intake manifold bolt pattern. Plugs are slightly angled which may interfere with some headers; I don't have any issue. Chambers are small (58cc I think?) which works well with dished 71 pistons to boost compression. I would buy the heads separately again for a small block build as they are plentiful and affordable. Also, with centerbolt valvecovers, mine have never leaked. Motor runs very good.

You will need rail type rockers, and when I fixed a leaky head gasket on my motor, I couldn't get much info about what the correct gaskets to use were, so I went all GM on gaskets and bolts, and had a friend buy them thru the dealer he worked at. Also, the springs are stock springs so one can't get too crazy with valve lift without swapping parts.

Check prices at Jim Pace or Scoggin Dickey, unless you have good dealer near you. Or find some used.

Best,
Tom

okinawa86vette

These heads were designed long before the vortec stuff came around, so no, they're not vortec style and any way.

Be careful about the compression. Use one of the online compression calculators to determine the cr with your stuff. It's entirely possible to end up with something too high. Not that it will, but it is something to keep in mind.

They are good heads and used to be one of the hot heads to get in their day. They can make a lot of torque with the right setup. I would probably use a good dual plane intake and a cam that's meant to make low end power to get the most out of them. L98's, for both the heads and intake, were never known for their long legs. Even bolting a high flow intake didn't do much to pick up high end on those motors.

And don't ever deal with Scoggin Dickey. I have had several bad experiences that cost me nearly $10k with them and I haven't heard too many good things about them from others. I know their prices are good, but they are not good people.

Chris

jackson

Thinner GM composition head gasket P/N 10105117 is correct & a good choice. L98's 58cc will push dished 71 L48 to about 10:1 static compression. L98 & a $70 Summit cam & lifter kit (K1103) will make a reliable & hot little street 350. With K1103, DCR will be about 8 to 8.1:1. Depending on exhaust ... will easily make 300-325hp at crankshaft.

71rdster

hensen1954

I am using them with headers, cam, torque plus, dual plane and true duals, alloy pulleys and water pump. Electric fan only.

With my 1981 pistons, I think I'm up to about 10 . 5 compression.

probably about 350 bhp.

Jason Staley

The heads used on my ZZ4 are pretty much the same heads, if not exactly the same ones. Anyway, to get better flow without porting the heads you can install Manley or Miloden valves.

I did a comparison between Manley 1.94" raceflow valves and my friends heads with generic 2.00" valves. Up to .300" lift, the heads were flowing the same amount. Above .300" his heads flowed more than mine, but I thought it was impressive that good smaller valves can flow as much as larger generic valves at the lower lift numbers where the valve is the main restriction point.

vintage-racer

Hi hensen1954, What type of headers are you using with the L98 heads? I've got Hooker side mounts. Did you have header/sparkplug clearance problems without using short reach plugs? Blair

hensen1954

Hello again,

have genuinly forgotten the make of the headers - bought them 2 years ago, but I do remember that they are in essence the wrong ones because they have round not d port shape.

However, I do not see that as a big problem so far. They are the long 4 into one. Angled plugs with these heads are no problem but I did change 4 of the plug caps to Lucas right angle type to clear the headers better.

Fitment and line up seem spot on.

L88Plus

Okinawa, I've dealt with Scoggin-Dickey for over 10 years, never had a single bad experience and my purchases there, over the years amount to tens of thousands of dollars. There are thousands of folks that have had very successful dealings with them as well. I've ordered from Summit 3 times and they've messed up my order every time.
Your remarks are considered vendor bashing and aren't generally allowed on most forums.

okinawa86vette

It is not vendor bashing. I dealt with them since I was in college at TTU over 10 years ago and never had a bad experience until I bought 2 motors from them. Both expired within 1000 miles.

The second one was a no expense spared build. Supposedly balanced and blueprinted and decked. There was no evidence of a balancing on the motor after I tore it down. The motor was destroyed because a piston failed. I asked for and was told the motor would have a 10:1 compression. After tear down and measurements, the motor had over a 12:1 compression with the heads, head gaskets, pistons, and decking.

I was lied to and cheated. As far as I'm concerned, I was not provided the services that I paid for. After a threat of a lawsuit and months back and forth on the phone with them, the finally sent me a new piston and rod. No ammends were made for the lack of balance and the incorrect cr.

When I asked for a new motor, correctly built, under warranty, they refused because I had raced the motor. When I bought the motor, I specifically told them I would be racing it on occasion and would it be covered under the warranty. They assured me over and over that it would. They cost me $6k in the second engine alone.

I don't see how this is vendor bashing in any way. This is the truth of what my experiences with SDPC were. The poor customer service when there was a problem, to the point where I would call, say who's speaking, get put on hold for 30 min before being hung up on, was one of the biggest issues. I should not ever have to ask to speak to the owner of the dealership because the manager won't speak to me.

If we can't warn fellow forum members of poor service and experiences, then what's the point? I am still paying for my bad experience with them and I would hate for someone else to experience the same.

My experience is not unique and at least 3 other racers in the west and mid texas areas have had very, very similar experiences. I won't get into details about theirs, since it was not something that happened directly to me.

Everyone is free to purchase from whoever they can trust and their wallet can handle. If you've had nothing but positive experiences, then please continue with SDPC. I'm just giving fair warning and the advice of buyer beware.


Chris

SDPC

Mr. Savaglio:

Although I was not employed at Scoggin Dickey when your had this bad experience, I have been filled in on the rest of the story that you are NOT throwing out for the CF members. I am looking at the letter that was sent to you, signed by the performance parts director and your salesman asking for you to send that engine back to us (at no cost to you of course) so that we could go through the engine and make things right.

It started with a misprint in the GM catalog, and you got the wrong replacement piston sent to you. When we received the piston back, it showed signs of being run pretty lean and you admitted to running a nice size shot of nitrous as well. Your salesman and the GM Performance Parts director tried to get the engine back from you to fix it, and you said you'd get back with them. But you never did. How much more did you expect them to do for you? Should they have driven to Colorado to pick up the engine? They offered to pay to get it back, all you had to do was crate it up. And I am sure that Scoggin Dickey would have compensated you for your labor as well, given the chance.

So feel free to share your experience with SDPC...but share the rest of the story too! And feel free to contact me if there's anything I can help with down the road.

Thanks.

okinawa86vette

First, I assure you I never even transported a bottle of nitrous in my car, let alone hooked one up. Any story that I "admitted" to using nitrous is pure fabrication. Unless a "nice shot" is simply pure, 6000 ft altitude air going through the intake. It was your employer's speculation that I ran nitrous.

Of course there was detonation. All of my tuning was done for 10:1 compression, not the 12:1 it came out to when I found out what parts were in it.

Did they inform you that pulling the motor would be at my expense? Over and over, I pleaded to at least split the labor and SDPC would not give a dime. I was told I could do it myself at no cost (even though I had just undergone a major back surgery fusing several vertabrae).

Mind you, this is all after threat of lawsuit. I chose not to spend the $3500 and time I was quoted to pull and send the motor back, especially considering I would have a vehicle that I wouldn't be able to sell because it had no motor.

I am not spreading ugly rumors of things that never happened. In fact, I never even mentioned the fact that I was sent the wrong piston and assured over and over it was the correct one before I installed it. In fact, I was told that what I was sent was the new part number and of course it wouldn't match what was in the motor already, but they were the same piston.


If you have anything else to add, such as other parts of the story I didn't share, like the nitrous I wasn't aware I had installed, please do so.

When other forum members have a bad experience with a company, there is no issue about them telling their story. I am not going to forget something that happened to me just because that company is a forum vendor.

Chris

HOGDADDY

I had the L98's on a 1980 305 w/ forged TRW flattop pistons years back that ran well.