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Discussion Starter · #1 ·
I just bought a GT shortblock with the intentions of using it with my 4V heads. I made numerous phone calls and read lots of posts that said the blocks are the same with the exception of mabye some timing cover bolts. WELL... I just got the GT shortblock today and found another slight difference that may prove difficult to deal with. When looking on the front of the block, there are 4 dowel pins on the GT block that are driven in. They are for the timing chain guides. On the cobra block these are threaded and the dowel pins are a different size. Sounds like no big deal but the dowel pins I must use (COBRA) are threaded with a much smaller thread than the hole the pressed in dowel pin leaves. If anyone has any tips, let me know. I guess I can tap it and have about 2 or three helicoils in those holes but I would rather avoid it if anyone has any ideas or has ran into this.
 

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I see you haven't gotten any responses to this question yet. Have you figured anything out? I too would like to know what others had to say as I wasn't aware of the difference you are talking about.
 

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If you need some dowels.. let me know.
I just went through the same thing when going from aluminum block to iron block. You may/may not have to plug a bolt hole on the chain cover (will be lower-right of water pump) as depending on what block you have there may not be a hole there for a bolt.
 

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Discussion Starter · #5 ·
I got the problem fixed. I found some 6mm to 10mm threaded inserts. The hole in the block has to be opened up slightly so you can tap it 10X1.5mm. It is not a big deal at all except finding the threaded inserts. I have a source for them if anyone needs them. They don't cost much, just hard to find locally.
 

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Discussion Starter · #6 ·
Oh yeah, on the timing cover... There was not a matching hole in the block (romeo) for one the timing cover bolts. The location of this should not cause a problem. I used a small amount of gasket sealant on the timing cover in that spot and I don't have a leak at all.
 

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Mike said he just put a small freeze plug in that hole in the over. I have heard of it done the way you mention also...just keep an eye on it for leaks.
 

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I put a freeze plug in mine since I run a blower.
The crankcase can get pressurized and I didn't wanna risk RTV being blown out On N/A engine I'd say RTV is just fine.
 

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Dowels

You will find several small differences between Romeo and Windsor blocks. There are at least 2 different size cam sprocket bolt thread sizes in DOHC 4V Heads, if you have the cams with the smaller hole you can't use the ARP Cam Bolts, although the Ford 10.9 bolts are plenty strong.

nmrapro50:banggears
 

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I think mine are 97 or 98 heads, do all of those have the same size cam sprocket bolt thread sizes?
 

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Cam Sprocket Bolts

I'll shoot some pics comparing the two bolt sizes and post them, there is a big difference. I'm not sure about which cams have which cam bolts, I discovered this difference when I ordered a set of 4 ARP Cam Bolts and found they would fit one set of cams and were to big for my other set of cams. I think I still have the part # for the small bolt size, if I can find it I'll post it with the photos.

nmrapro50:banggears
 

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NMRAPRO, why don't you help get that 2v to 4v head swap FAQ going? Get in touch with Eric Brooks as he is looking for the info to put the FAQ together.

It would be a big help to the rest of us.
 

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Even 2v to 2v there are a lot of small differences - even withing plant families over the years.

I got a really informative mag the other week from my friends that showcases the differences between all the 2v parts out there - small changes in the heads, cams, chains, everything. I have it at work, I'll get the name of it and if there's interest I can scan it....
 

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Someone needs to make a swap kit, like CDC is doing with the BIW cars. Where if you don't need some pieces, they can be deducted from the kit. For instance I have an iron GT block and a complete set of heads, minus the wiring, it would be nice to go one place and get the rest of what I need.
 

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why not just use the GT chain guides that are supposed to run on those dowl pins?

Any issues w/ that? I was under the impression that the 4v and 2v main cam gears were in the same place....

SJ
 

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I was told that you could do that. Use the 2v motor and timing cover, just needed the heads, cams, intake, comp. and wiring harness parts from the cobra.
 

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I could be wrong, but seems like I heard somewhere that the cobra chains and guides were polished to reduce friction on the guides and not wear on them as quickly.

Still wouldn't mean you couldn't use the gt guides though.
 

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subscribing some good info here.
 

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Can't you buy a new Cobra Short Block for around $400. If so just get the correct block and call it a day.
 
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