Budget'ish '69 302 Garage Rebuild...

[bulletpruf]

Time to get moving on the project barn-find '69 Bronco that I bought way back in 2019.

I got it running several years ago but the original 302 block is cracked, so that has to go.

I'll yank the engine/trans/transfer case this weekend.

I sourced a 302 out of another early Bronco to build for it. Yes, I know I could get a late model roller block and build that, but I'm going to stick with this one.

Plan is to do everything in the garage without going to the machine shop. I don't have anything against machine shops, but I prefer to do the work myself if I can.

Assuming the bores are in good shape (I'll check diameter and taper) and it mags fine (I have a magnaflux setup), I'll do a ball hone and call 'em good. I have 240 and 320 grit hones that I used for my 7.3 idi diesel build, so one of these should work.

I'm inclined to source a set of reasonably priced flat top pistons; I'd like to get compression to 9.5:1 but not sure I can get there with the pistons available. Given my calculations, I can get to about 9.1:1 with some reasonably priced hyper pistons. I'll press pistons on and off in the garage.

If the crank mic's and mags ok, I'll do the shoelace and sandpaper cleanup on it. I've done this before and it works fine.

I'll use some GT40P heads that I picked up for $100 (yes, I got lucky). I'll check to make sure they're not warped, mag them, and plan to pick up a granite surface plate to see if I can do a redneck surface in the garage. I plan to do a backyard valve job with some Neway cutters.

A buddy gave me a Holley dual plane intake that I plan to use. I know an RPM Air Gap is probably the best option but I'm limited by hood clearance.

For a carb, I have a few Quadrajets (these work well in a 4x4 application) but I'd rather not have to run an adapter. Now I'm leaning towards a Holley 670 cfm Truck Avenger.

I plan to use the double roller timing chain on my existing engine; it has about 10 minutes of run time on it.

Cam is TBD. Could use some help sourcing a decent flat tappet hydraulic.

Ignition is TBD. I have a box of 289/302 distributors somewhere in the garage. Any recommendations here?

I have a set of headers; I need to see if they'll work with the GT40P heads. If not, I'll source some that will work.

What's a reasonable guess on hp/torque? I'd be happy with 300 hp, 350 ft/lbs.

What did I miss?

Scott

 

[bulletpruf]

Got the spare 302 - the one that I plan to build - partially disassembled yesterday. Bores are 4" (i.e., it hasn't been bored) and looked good with no ridge. FOMOCO timing chain. I did not remove the oil pan.

Anyway, seems like a bit of a hodgepodge - the intake is a D30E, dated 1973, IIRC, so I was expecting D30E heads and block.

The heads are either D50E or D60E. Nothing special and unlikely to have hardened valve seats.

Block is D40E, dated 4H26 (1974 August 26), so it really doesn't match up with the heads or intake.

It's no big deal that nothing matches up, but I'd prefer something that hasn't been messed with.

 

[DirtDonk]

Engineering numbers for different components don’t have to match. They often don’t because one part number may carry over for several model years. Whereas others might be changed for the very next year.
They may have used a D3 intake for several years. A D4 block for several years as well.
I would think D5 or D6 heads would absolutely have hardened seats. Unleaded was already in use and passenger cars, and utility vehicles like Broncos (that were often registered as passenger vehicles), got catalytic converters starting in 74 and 75 in some regions.
So unleaded fuel was already a thing and a head designed for a 75 or 76 vehicle could easily have had hardened seats.

Although the casting dates shouldn’t be too far apart, I wouldn’t think. But there’s no guarantee of that either, during the time when so many things were changing.

What year is this engine supposed to be from?

 

[bulletpruf]

Engineering numbers for different components don’t have to match. They often don’t because one part number may carry over for several model years. Whereas others might be changed for the very next year.
They may have used a D3 intake for several years. A D4 block for several years as well.
I would think D5 or D6 heads would absolutely have hardened seats. Unleaded was already in use and passenger cars, and utility vehicles like Broncos (that were often registered as passenger vehicles), got catalytic converters starting in 74 and 75 in some regions.
So unleaded fuel was already a thing and a head designed for a 75 or 76 vehicle could easily have had hardened seats.

Although the casting dates shouldn’t be too far apart, I wouldn’t think. But there’s no guarantee of that either, during the time when so many things were changing.

What year is this engine supposed to be from?

Correct, engineering numbers don't necessarily have to correlate, but the date codes should be reasonably tight for an engine that was relatively common. I'm guessing the date codes on most engine components (i.e., heads, blocks, and intakes) would normally fall within about 2 weeks of each other.

The seller wasn't sure what year it was supposed to have come from. He got it from a local shop that rebuilds early Broncos so it was just one that got yanked in favor of a Coyote.

 

[DirtDonk]

Yeah, I guess that wide spread between the intake manifold versus the block is a pretty sure indicator that it was fiddled with over the years.
What are the date codes on the heads?

Cylinder heads can often be explained away by either needing a valve job and using an exchange service instead of rebuilding the original heads. Or, someone wanted to update to leaded use and so got later heads.
An intake manifold might’ve been swapped back in when somebody stole the four barrel off of it! Or whatever reason…

 

[bulletpruf]

Yeah, I guess that wide spread between the intake manifold versus the block is a pretty sure indicator that it was fiddled with over the years.
What are the date codes on the heads?

Cylinder heads can often be explained away by either needing a valve job and using an exchange service instead of rebuilding the original heads. Or, someone wanted to update to leaded use and so got later heads.
An intake manifold might’ve been swapped back in when somebody stole the four barrel off of it! Or whatever reason…

Good points on the cylinder heads. I'll have to check the date code.

Thanks