Rembrant Posted February 16, 2022 Share Posted February 16, 2022 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!! Link to comment Share on other sites More sharing options...
ratdude747 Posted February 17, 2022 Share Posted February 17, 2022 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!! 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/ Link to comment Share on other sites More sharing options...
1986F150Six Posted February 17, 2022 Share Posted February 17, 2022 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/ 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. Link to comment Share on other sites More sharing options...
IowaTom Posted February 18, 2022 Author Share Posted February 18, 2022 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. 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. Link to comment Share on other sites More sharing options...
FuzzFace2 Posted February 18, 2022 Share Posted February 18, 2022 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. 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 ---- Link to comment Share on other sites More sharing options...
1986F150Six Posted February 18, 2022 Share Posted February 18, 2022 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 ---- The F.I. head has about the same combustion chamber volume as the 240, but the F.I. head has fast burn characteristics. Link to comment Share on other sites More sharing options...
IowaTom Posted February 21, 2022 Author Share Posted February 21, 2022 The F.I. head has about the same combustion chamber volume as the 240, but the F.I. head has fast burn characteristics. On she goes! Used the hoist for the manifold too. A real hernia-maker! Link to comment Share on other sites More sharing options...
mat in tn Posted February 21, 2022 Share Posted February 21, 2022 On she goes! Used the hoist for the manifold too. A real hernia-maker! oh us 300 guys understand . but when using the hoist you might as well assemble those on the head while on the bench also. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 21, 2022 Share Posted February 21, 2022 On she goes! Used the hoist for the manifold too. A real hernia-maker! Link to comment Share on other sites More sharing options...
IowaTom Posted February 21, 2022 Author Share Posted February 21, 2022 oh us 300 guys understand . but when using the hoist you might as well assemble those on the head while on the bench also. If I had it to do over, yes, I'd have bolted on the manifold before dropping the head! Link to comment Share on other sites More sharing options...
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