I searched last night but didn't find a definitive answer.

Scenario: You've got a bitchin' (this is a Camaro site, you're allowed to say bitchin' here) set of heads and intake from an LT1, but you've eliminated basically every LT1-specific feature from your engine with the exception of reverse coolant flow, and there's nothing keeping you from using an aftermarket SBC (Dart, Motown, whatever) block for more cubes (not to mention an aluminum block for less weight).

The simplest approach is to just weld the reverse coolant openings at the ends of the heads closed as I've seen done, then drill the required holes using an SBC gasket as a template. Then you'd have to drill the heads on the intake surface and drill and tap the intake manifold for fittings to use for coolant crossover lines, and add a "box" for a thermostat and filler neck. Is there anything I'm missing?

However, if you wanted to "convert" the block to reverse coolant flow, what steps would you take? I saw a picture Bret posted in another thread of one Engine Masters engine that had plumbing from what I assumed was a blocked off water pump up to two Ys (one for each head) which went into the crossover passages of the intake manifold. Other lines came out the bottom of the block on each side (or so it appeared) and fed back into the system, and it had a separate filler neck/thermostat assembly.

Would it be possible to weld the reverse flow openings of the LT1 heads closed and then plumb them separate of the intake manifold? In other words, drill an opening in the front and back surface of each head as opposed to the intake surface and add fittings to connect them in the rear and feed them from either side of an SBC water pump like in the Engine Master's setup above, without drilling/tapping the intake manifold?

While we're on the subject, does anyone have a coolant flow diagram for the LT1 and SBC?

Bottom line, I don't want to have dozens of hoses running this way and that, and I'd like to do the minimum amount of work required to my heads and intake to run them on a Motown block, but it'd be nice to have reverse coolant for an additional margin of safety.

Any help is greatly appreciated. Thanks!

 

Jim. I am going to build a water pump based on the LT1 casting but instead of going back into the block it feeds all four corners of the heads. fairly simple. most say it is a waste but I have made up my mind.

You will have to get your heads converted back to SBC Gen-I to use them on the Gen-I block. To get the coolant in you will have to drill the hols in the intake surface as well. Now on mine I am going to vent the same way as a LT1 using the Center ports in the heads. Those are the ones you have pipe plugs in if I remember correctly.

This is the same basic setup Smokey cam up with back in the late 50s early 60s

 

Honestly, I would say why bother? Are you really going to spend the cash for a big inch aluminum small block and use a set of castings that might have a 190cc intake runner (I'm guessing, you may have a set of 227 AFRs for all I know)? Sounds counter productive to me. Sell the LT1 stuff and get a killer set of heads for it.

You could probably get away with enlarging the steam holes if you're still serious about it. I really wouldn't worry about doing this since most aftermarket blocks have better oiling and cooling setups than their production counterparts.

 

They are AFR 215RR heads.

Bret

 

See, I didn't know that, but I guessed pretty good.

Personally, I'd try to steal those 18 degree heads from you Bret.

 

You guessed that I had a $6,000+ set of AFR 215cc raised runner heads with 2.10"/1.625" Ti valves that flow 335 cfm? Amazing.

That and the matching $2,850 Hogan's intake are why I wouldn't just start over.

 

I'm getting raked over the coals here. Had I known you weren't talking about a normal set of LT1 heads I would have said something else.

Nice setup BTW.

 

Where have you been for the last 4 years? I thought I (or at least my engine) was pretty well known around here.

 

Jim,

I have to ask what is your goal? What hp? To rule the world? Have a kickbutt smallblock V8 in an Rx7? It seems to me that at this point you'd be ready to toss it in the car and have some fun. Why stop, spend more money for a block for a little bit more hp? Why not just spray as you see fit and enjoy the motor. Then, when you decide you need more power, change directions.

My dad man told me once:

Sometimes you can have more cents than sense.

To each his own. Regardless, I'll still be directory surfing when you post update pics .

Ryan

 

For several reasons. First, I'll drop another 50-60 lbs. in weight by going with an aluminum Motown short block, and get more cubes as a fringe benefit. Second, I'll be able to make the same power levels with less cam, making the car a little friendlier, and I'm pushing back towards streetable at this point. And third, the Jesel belt drive I just bought to add a cam sync sensor to won't fit an LT1 without a bit of work, but it'll go right on a Motown block.

There's nothing "LT1" left (except reverse coolant flow) that would keep me from using an SBC at this point, and I've wanted a Motown since they were introduced. I could switch to an LS1 instead, but they don't fit the car as well (intake interferes with the firewall, requiring them to be mounted farther forward), and I've got too much money in my top end and engine cradle to switch now. An aluminum block SBC is sort of the best of both worlds.

Of course, it goes without saying that an RX-7.0 badge would look pretty cool.

 

The routing of this is not really hard... Ellis pointed out the big points of this conversion. Basically you need to get those heads back to SBC shape and then you run external lines from the water pump to a T, then to each end of the cylinder head. Pull the coolant out of the block via the drain plugs on the side of the block.

Only thing I would advise on the heads is make sure that someone looks at them to see that they will work with the cubes and the RPM range you want to run. If you are going to cut that RPM level down from before they should be fine.

Bret

 

Right. But can you tap into the coolant passages on the ends of the cylinder heads, or do you have to do it on the intake face? I just had my intake powder coated and I don't want to have to do any work on it if I can avoid it.

~7,000-7,200 rpm?

 

Yes you can simply tap in and install fittings I am going with AN fittings and I will bend up hard lines using aluminum Fuel line(5/8)

 

You can machine the powdercoating without a issue.

As for the heads.... a head for a 396 turning 7,600rpm should work awesome on a 427 turning 7,000rpm.

Bret

 

What are you trying to do now Jim?

I like the big small block idea... so much so that I'm doing that too.
Just not with a set of 23º heads. Almost impossible to get too much head on a 427+ ci small block.

Good luck.

-Mindgame