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Replacement head question

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IowaTom

Replacement head question

Guys - My '85 F150's old head was beyond repair and the machine shop had a very good replacement 240 head for my 300 c.i.
I notice threaded holes just above the manifold, opposite the spark plug side of the head and believe them to be for fuel injectors. Since my truck is carb'ed, I'm thinking I should plug them, right?
If so, what size plugs do I need?
As always, thank you!!

'85 F150 XLT 4X4 with 300 c.i. six & NP435 four speed.
'63 Studebaker Avanti - 350/TH350
'59 Rambler Super - OHV 6 with 3-speed OD
'58 Studebaker Scotsman sedan - 289 with 3-speed OD

Gary Lewis

Re: Replacement head question

Administrator

Tom - If I understand which holes you mean I don't think that the threaded holes, circled in red, are for injectors. I don't know what they are for, but I suspect they are blind, meaning that they go nowhere. But you can check that out by turning the head up and filling those holes with brake cleaner or somesuch.

However, the hole circled in green might be for an injector. As far as I know, gasoline injectors are not screwed in but go into a recess, like the one in green, using o-rings to seal them. But you can check that to see if that hole goes into an intake passage, and if there are 5 more of them just like that one into intake passages.

If they are for injectors you can seal them with brass cups. I don't know the size, but I ran Big Blue's engine for over a year with those holes plugged with brass cups. So I'm sure we can find out what size they are. I put them in with a smear of non-hardening sealer and it worked fine.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

85lebaront2

Re: Replacement head question

Administrator

In reply to this post by IowaTom

Those may go into the exhaust ports and would be for the smoke grinder (Thermactor system) if they are threaded. If not threaded do as Gary recommends. If your truck does not have that, they can be plugged. They should be a 7/16-20 thread, but could be 3/8-24. Which ever they are get six headless Allen screws (set screws are good due to the point) and put them in tightly.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

IowaTom

Re: Replacement head question

Thank you, Guys!

It's the one circled in green...and that's slick how you can do that, Gary. :-)

All six holes are threaded, so I'll use my taps to figure out which size then get those plugs. Sure can't wait to get this baby running again!

'85 F150 XLT 4X4 with 300 c.i. six & NP435 four speed.
'63 Studebaker Avanti - 350/TH350
'59 Rambler Super - OHV 6 with 3-speed OD
'58 Studebaker Scotsman sedan - 289 with 3-speed OD

Gary Lewis

Re: Replacement head question

Administrator

I think Bill is right, the green one is probably for the AIR (air injection/reaction) thermactor system to inject air into the exhaust. If so, and if it is threaded, you can plug it with a set screw, although I'd use anti-seize on the threads to seal them.

But check to see where that hole goes.

Gary, AKA "Gary fellow": Profile

Rembrant

Re: Replacement head question

In reply to this post by IowaTom

That would be a 300 EFI cylinder head, not a 240. I don't think there was any air injection happening when the 240 was still in production, was there?

Here's a picture of what the air injection pipe looked like on the 300 EFI. It had little drop down pipes that fit into each of those holes with threaded fittings.

1994 F150 4x2 Flareside. 5.0 w/MAF, 4R70W, stock.
1984 F150 4X2 Flareside. Mild 302 w/ 5spd. Sold.
1980 F150 4X4 Flareside. 300i6 w/ 5spd. Sold in 2021.
1980 F100 4X2 Flareside. 351w/2bbl w/NP435. Sold in 1995

Gary Lewis

Re: Replacement head question

Administrator

I think you are right, Cory. I was sure there wasn't any EFI, but couldn't find anything on the thermactor. But your pic is spot-on.

Gary, AKA "Gary fellow": Profile

mat in tn

Re: Replacement head question

so, the real question here is. is it a 240 head?

mat in tn

Re: Replacement head question

the threaded holes on the gasket surface are the ones needed to mount the manifolds. the un threaded look to be for injectors as I do see a taper, yet I do not see threads

Gary Lewis

Re: Replacement head question

Administrator

In reply to this post by mat in tn

If we had a casting # I might be able to tell.

Gary, AKA "Gary fellow": Profile

Rembrant

Re: Replacement head question

In reply to this post by mat in tn

mat in tn wrote

so, the real question here is. is it a 240 head?

I don't think a 240 head would have holes for an air injection manifold. I don't think the carbed 300 even got that. I thought that only showed up when the 300 got EFI in 1987. Further evidence is those two threaded holes being close together...I didn't think that the carbed 300 had those, either. The 300 head got a few extra threaded holes on that side in 1987 when they switched to the two piece exhaust manifolds. A carbed head should only have one threaded hole there.

I'm not a 300 expert by any means, so I could be way off base here. We need David or Jonathan, or another resident 300 expert!!

ratdude747

Re: Replacement head question

I think it was Cali thing... at least in 1984 they existed both ways (as I found out when researching my engine).

If they are 240's, the compression will be way higher than stock. If that's what you want, then great... but if not, buyer beware!

A good read on how to ID the two heads:

https://www.foleyengines.com/tech-tip-202-ford-csg649i-ford-300-cylinder-head-differences-made-easy/

1984 F150: 300 L6, AOD, RWD. EEC IV / TFI, Feedback Carter YFA Carb. Stock everything but radio (for now).

1986F150Six

Re: Replacement head question

Administrator

When using a 240 head or F.I. 4.9L head as a replacement for a carbureted 300/4.9L engine the compression will be increased ~.5 point.

IowaTom

Re: Replacement head question

From the kidney shape of the combustion chamber, I believe it to be a 240 head. It's replacing the same kind (that was cracked) on my engine, which left the factory FI but converted to a 1bb carb.

I think a previous owner had some work done on this engine during it's life as fuel injected since the head was replaced and later cracked. I hope to avoid that problem in the future, if it's possible.

Will that higher compression ratio need a higher octane than 87? I don't plan to be hauling or towing with the ol' girl.

'85 F150 XLT 4X4 with 300 c.i. six & NP435 four speed.
'63 Studebaker Avanti - 350/TH350
'59 Rambler Super - OHV 6 with 3-speed OD
'58 Studebaker Scotsman sedan - 289 with 3-speed OD

FuzzFace2

Re: Replacement head question

Like Cory I dont know of any 240 head that had FI or air injection so I would call that a 300 FI head.
The FI head will have more manifold threaded hole than a non-FI head and if you can I would use them other wise just run what the non-FI head uses for the manifolds.
I am running FI exh manifolds with the log intake on a non-FI head so 2 less bolts and no issues so far.

I have not heard of a FI head upping the compression like the 240 head but as posted I seen the 240 to be .5 so nothing to worry about on the gas you run.

If them holes are not needed cap them as pointed out.
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

1986F150Six

Re: Replacement head question

Administrator

The F.I. head has about the same combustion chamber volume as the 240, but the F.I. head has fast burn characteristics.

IowaTom

Re: Replacement head question

On she goes!

Used the hoist for the manifold too. A real hernia-maker!

'85 F150 XLT 4X4 with 300 c.i. six & NP435 four speed.
'63 Studebaker Avanti - 350/TH350
'59 Rambler Super - OHV 6 with 3-speed OD
'58 Studebaker Scotsman sedan - 289 with 3-speed OD

mat in tn

Re: Replacement head question

oh us 300 guys understand . but when using the hoist you might as well assemble those on the head while on the bench also.

Gary Lewis

Re: Replacement head question

Administrator

In reply to this post by IowaTom

Gary, AKA "Gary fellow": Profile

IowaTom

Re: Replacement head question

In reply to this post by mat in tn

If I had it to do over, yes, I'd have bolted on the manifold before dropping the head!

'85 F150 XLT 4X4 with 300 c.i. six & NP435 four speed.
'63 Studebaker Avanti - 350/TH350
'59 Rambler Super - OHV 6 with 3-speed OD
'58 Studebaker Scotsman sedan - 289 with 3-speed OD