C4 flex plate 164 tooth 10.5" bolt pattern HELP

acrman404a · 02/09/06, 09:12 PM

I have a 67 Bronco w/ 73 C4 trans and 351w engine need to replace flywheel however Ford says they never made a flywheel with 164 teeth & 10.5" bolt pattern. Now Im thinking I might have the wrong flywheel maybe a 50oz instead of the proper 28oz. balanced flywheel. I want to put a new crate engine in my rig but do not want to destroy the new engine. Does anyone have specs on the bronco torque converter bolt pattern. May be I have the wrong torque converter??? does anyone have a tranny out so they can go measure the bolt pattern is it 10.5" or 11.4". My old flywheel is still good but I don't know how to determine the weight unbalance 50oz or 28oz.

**t.lay** · 02/09/06, 09:23 PM

I'm not a 100% on this but I was thinking these were 159 tooth flex plates - I've got a "73 with a c4. I've got a spare flex plate. then again it's a 302.

**73stallion** · 02/09/06, 09:28 PM

what engine are you sticking with, 351? all 351 engines were 28oz balance, and there was either 157 or 164 tooth.

acrman404a · 02/09/06, 09:41 PM

Ford says it takes a 164 tooth 11.4" bolt pattern. i was thinking this was something unusuall for broncos (10.5" bolt pattern) can you go out and measure the bolt pattern its measured the long way across the wheel. Yes 351w will be put back in its the same flywheel as the 302 28oz unbalance

**broncnaz** · 02/09/06, 10:58 PM

Sounds like someone may have swapped to the small bellhousing so you will need the smaller 157 tooth flex plate. Most bronco's came with the bigger flex plate and bellhousing. but some people have found the small bellhousings on there stock broncos. You may want to count the teeth on your flexplate. C4's are known for having weak bellhousings and its hard to always find the correct bellhousing so many people swap the smaller one on. It doesnt matter which flexplate you use as long as you have the correct bellhousing and torque converter for that flexplate.

**toddz69** · 02/09/06, 11:40 PM

Quote:

Originally Posted by acrman404a

I have a 67 Bronco w/ 73 C4 trans and 351w engine need to replace flywheel however Ford says they never made a flywheel with 164 teeth & 10.5" bolt pattern. Now Im thinking I might have the wrong flywheel maybe a 50oz instead of the proper 28oz. balanced flywheel. I want to put a new crate engine in my rig but do not want to destroy the new engine. Does anyone have specs on the bronco torque converter bolt pattern. May be I have the wrong torque converter??? does anyone have a tranny out so they can go measure the bolt pattern is it 10.5" or 11.4". My old flywheel is still good but I don't know how to determine the weight unbalance 50oz or 28oz.

It will be a 28 oz. flexplate (manuals use flywheels). Yes, there is a very good chance you have a 164 tooth flexplate with the 10.5" bolt pattern. This issue has been debated numerous times over the years on the EBML and Broncofix and the concensus seems to be that Ford used the small (i.e. 10.4") bolt circle on EB C4s from '73 up until at least '75 and maybe into '76. All of the rest of the years forward use the 11.4" pattern. If your torque converter and flexplate are good (you seem to indicate they are), then simply bolt your flexplate onto your new engine (assuming it's an older 28 oz. balanced engine) and you're good to go. This bolt circle problem often comes up when folks want to get a 50 oz. flexplate to use with their 5.0 conversions. The solution is to get their existing flexplate rebalanced or change the converter to the newer bolt pattern and buy an AOD flexplate.

Todd Z.

RFR2212 · 02/10/06, 12:59 AM

http://www.performanceautomatic.com/index.htm

I used them when using a 5.0 stang motor w/ a manual converted to a c4. Got some odd sized/balenced plate, and they had good prices years ago when I bought it, not sure now, but figured I'd throw it out there.

SaddleUp · 02/10/06, 03:08 AM

If you have a 351W now and replace it with another 351W crate engine then it will probably be balanced the same and requie no changes. (All of the 351W and 5.8 stock engines were the 28 oz.) If your putting a 5.0 engine in then that may not be the case. At any rate find out what you need first (If anything) and then post it here (I have a couple of different ones including a 50 oz 157 tooth 10.5" which was a special order) to see if anyne has what you need. If not then Summit probably has it.

**ransil** · 02/10/06, 04:00 AM

You can find some info here:

http://www.bulkpart.com

http://www.bulkpart.com/Merchant2/me...egory_Code=C-4