Difference in 6 and 7 bolt heads

[baker41o7]

I have a 6 bolt block. Im buying a head and Im wondering if it matters if it get a 6 or 7 bolt head. Ive heard that the bolt sizes are different somthing like the 7 bolt head has to get drilled out. Is that true and is the only difference that the cam gears are on the opposite side?

 

[brassc2007]

the cam gears are on the same side the only way a dsm has cam gears on the passanger side is if it is a 420a and that will not work on a 4g block

 

[1gDSM4g63]

A 7 bolt head uses bigger studs and bolts, 12mm. Stay with a 6 bolt head, it flows better and next search the forums.

 

[baker41o7]

the cam gears are on the same side the only way a dsm has cam gears on the passanger side is if it is a 420a and that will not work on a 4g block

My bad... I dont know what I was thinking

 

[baker41o7]

A 7 bolt head uses bigger studs and bolts, 12mm. Stay with a 6 bolt head, it flows better and next search the forums.

Thaanks, and I tried but its not always that easy to find some of the things Im looking for with the search option.

 

[Jeff99GS]

The 6 bolt head 89-92 have the 12mm bolts and the 7 bolt head 93-99 have the 11mm head bolts.

You NEED to have the holes milled on the 7 bolt head to fit the lager bolts. Remember, one of those bolt holes has the oil supply flowing around it. If you put a larger bolt in that oil feed hole it could block off a substantial amount of oil to the Cams/HLA's/Rockers.

The 1g head also has MUCH larger intake ports. Some people think they flow better for high hp applications. SOME people think the 2g is better tho cause it creates a higher velocity. I myself prefer the 6 bolt head.

 

[the_mork]

A 7 bolt head uses bigger studs and bolts, 12mm. Stay with a 6 bolt head, it flows better and next search the forums.

I think you have this a little bit backwards, probably just a slip. A 7bolt head has smaller head studs. A 1g head has larger ports which some people say flow more than the smaller 2g ports but the 2g ports provide better velocity. The debate goes back and forth but it doesn't appear anyone has definitive answers on which is better. Generally the 2g head is supposed to provide better low and mid throttle but the 1g head is supposed to flow better in the very top ranges. I'm not sure I agree with that especially after seeing what a different intake manifold can do for a 2g head up top. It is also important to note that there are 1g 7bolt heads and 2g 7bolt heads. There are only 1g 6bolt heads. Depending on the year of the 2g head you may need to tap the intake cam in order to move the cam angle sensor.

 

[baker41o7]

I think you have this a little bit backwards, probably just a slip. A 7bolt head has smaller head studs. A 1g head has larger ports which some people say flow more than the smaller 2g ports but the 2g ports provide better velocity. The debate goes back and forth but it doesn't appear anyone has definitive answers on which is better. Generally the 2g head is supposed to provide better low and mid throttle but the 1g head is supposed to flow better in the very top ranges. I'm not sure I agree with that especially after seeing what a different intake manifold can do for a 2g head up top. It is also important to note that there are 1g 7bolt heads and 2g 7bolt heads. There are only 1g 6bolt heads. Depending on the year of the 2g head you may need to tap the intake cam in order to move the cam angle sensor.

Well I decided to go with a 6 bolt block and head. The block is already bored over .020 and Im going to stroke it and was wondering what everyone is using and what has worked best. Like Eagle 100mm crank, Eagle H Beam Rods, and Wiseco Pistons

 

[snowborder714]

Please do some searching. You can search by member and find out who's running a 2.3 and then look at their parts list.