Engine Build question

[White5.0]

ok i have a stock 302 block from a 1990 mustang...it has been bored .030 but has not been decked yet. I am going to take it to get decked soon and i was wonering what an ideal gap from piston TDC to the block deck would be? or should i get it zero decked so the deck is even with the piston at TDC?
basically, what should i tell the machine shop to do when i take my block to get decked?

would zero decking cause too much compression with a 58cc or 60cc head? here are the pistons i am using, speed pro with only 2 valve reliefs:
http://store.summitracing.com/partdetail.asp?part=TRW%2D8KH120CP30&autoview=sku


this is going to be a naturally aspirated 306 street car.

[Pure Stock]

You going to be using aluminum cylinder heads?

[White5.0]

You going to be using aluminum cylinder heads?

yes....im pretty much dead-set on using AFR 165's

[Pure Stock]

I say zero deck it. C.R. *should* be around 10.25-10.5 with the 58 cc combustion chambers. Ought to be a fun street 306 with a nice torque band with the 165's. Figure out what intake you'll run on it?

[White5.0]

I say zero deck it. C.R. *should* be around 10.25-10.5 with the 58 cc combustion chambers. Ought to be a fun street 306 with a nice torque band with the 165's. Figure out what intake you'll run on it?

I have a cobra intake as of now, and i know it is somewhat of a bottleneck when compared to other intakes out there, but it's what ive got so im gonna work with it for now.

how will the compression ratio differ with a 60cc chamber?

will i have to take the block with the rotating assembly installed in order to get it zero decked? or can i just give them the block and rotating assembly separated and they can measure parts?

[Pure Stock]

I have a cobra intake as of now, and i know it is somewhat of a bottleneck when compared to other intakes out there, but it's what ive got so im gonna work with it for now.

how will the compression ratio differ with a 60cc chamber?

will i have to take the block with the rotating assembly installed in order to get it zero decked? or can i just give them the block and rotating assembly separated and they can measure parts?

.29-.30 less compression with the 60cc combustion chambers.

You would think a reputable machine shop would be able to calculate where the piston will be in relation to the deck height and remove the required amount of material to zero deck it. It wouldn't hurt to give 'em a call and see what they recommend though.:awsome:

[White5.0]

.29-.30 less compression with the 60cc combustion chambers.

You would think a reputable machine shop would be able to calculate where the piston will be in relation to the deck height and remove the required amount of material to zero deck it. It wouldn't hurt to give 'em a call and see what they recommend though.:awsome:

thanks for all the info!.....i was just afraid of the compression being a bit too high if i zero decked it with those flat top pistons.

Are there any machine shops that you would recommend, or that anyone else reading this would recommend? When the block was bored it was taken to Brougher's machine shop on 51 near century 3 mall and they did a good job on it, i was thinking taking it back to them.

[madmaxin22]

that cobra intake is a nice one for the 165's... i had that same setup... if you want to get a good port job, tmoss on the corral does great work at a reasonable price on the lowers and its well worth it, i switched to a performer cause i found a good deal otherwise i was gonna send him my cobra lower. he ended up porting the performer lower and he did a great job... glad to see your making progress... i still miss that car!!!!

http://videos.streetfire.net/video/d37f26c6-f98e-4ee7-b104-9ded1279dd59.htm

[White5.0]

that cobra intake is a nice one for the 165's... i had that same setup... if you want to get a good port job, tmoss on the corral does great work at a reasonable price on the lowers and its well worth it, i switched to a performer cause i found a good deal otherwise i was gonna send him my cobra lower. he ended up porting the performer lower and he did a great job... glad to see your making progress... i still miss that car!!!!

http://videos.streetfire.net/video/d37f26c6-f98e-4ee7-b104-9ded1279dd59.htm

Hey mike....its funny i JUST watched that video on streetfire the other day...i searched for '87 GT' and saw that and was like "...wtf? thats the car i bought!!!" hahaha

but yeah the car is moving along slowly with college and everything but im really excited to finish it...don't worry im taking good care of it, its sitting in a garage all covered up, not sitting outside rotting or anything!

[madmaxin22]

Hey mike....its funny i JUST watched that video on streetfire the other day...i searched for '87 GT' and saw that and was like "...wtf? thats the car i bought!!!" hahaha

but yeah the car is moving along slowly with college and everything but im really excited to finish it...don't worry im taking good care of it, its sitting in a garage all covered up, not sitting outside rotting or anything!

thats funny... hope you have as much fun in it as i did but w/o all the headaches i had over the years.. theres another vid on that site idleing.. i watch them every now and then when im feeling down

[White5.0]

yeah i saw the idling one as well...makes me really eager to finish it up, but i still have a long way to go

[mlowry1260]

Get it zero-decked. a 4.030" bore, 3" stroke at zero deck, w/ .039" h/g, 6 cc valve notches and 58cc heads will only be 9.62 to 1. With steel rods you want to keep the quench height (distance from top of piston to flat surface of head) at a minimum of .035". A tight quench height setting helps fight detonation.

When a good machinist cuts the block deck he also squares it to the crank. production block are typically off end to end & side to side. Who's going to do the machine work. Let the machinist check the bores before you order the pistons.

I have a excel spreadsheet I use to calculate compression if you want it.

[White5.0]

Get it zero-decked. a 4.030" bore, 3" stroke at zero deck, w/ .039" h/g, 6 cc valve notches and 58cc heads will only be 9.62 to 1. With steel rods you want to keep the quench height (distance from top of piston to flat surface of head) at a minimum of .035". A tight quench height setting helps fight detonation.

When a good machinist cuts the block deck he also squares it to the crank. production block are typically off end to end & side to side. Who's going to do the machine work. Let the machinist check the bores before you order the pistons.

I have a excel spreadsheet I use to calculate compression if you want it.

thanks for the info...that helps as i wasnt sure what size head gasket to use too...it looks as if ill get the deck zeroed and squared.

Also wondering what machine shops in the area have a good rep? like i said, the one i went to (Brougher's) did a good job on the bore...has anyone else gone there to get work done?

[badf250]

thanks for the info...that helps as i wasnt sure what size head gasket to use too...it looks as if ill get the deck zeroed and squared.

Also wondering what machine shops in the area have a good rep? like i said, the one i went to (Brougher's) did a good job on the bore...has anyone else gone there to get work done?


A friend has Broughers build all of his race only 351W's, and our shop uses him for machining of cylinder heads, and rear end work. Never had a problem. The race car is very competitive at the Motordrome.

[White5.0]

A friend has Broughers build all of his race only 351W's, and our shop uses him for machining of cylinder heads, and rear end work. Never had a problem. The race car is very competitive at the Motordrome.

thats good to hear, although i never heard one bad thing about them i really never heard anyone mention them so i wasn't sure...they seem like a good shop

[Rodeheaver's]

if they are close to you yes they are a super good shop, and yes have the machinest check the bores before you order the pistons , a comp bore job requires all the pistons to be miced and dedicated to each bore(both checked at same temp), and each bore finished to the appropriate piston.. i have seen alot of stock 5.0 short blocks be super close to 0.0 deck heigth, and imo, it is more important to square the block than to have 0 deck heigth, but both should be accomplished by the one job..

[phillysrt4]

A friend has Broughers build all of his race only 351W's, and our shop uses him for machining of cylinder heads, and rear end work. Never had a problem. The race car is very competitive at the Motordrome.

do they specialize in 351W's, or are their machines programmed to handle other blocks? Not that I can afford it now, just curious.

[Rodeheaver's]

do they specialize in 351W's, or are their machines programmed to handle other blocks? Not that I can afford it now, just curious.
actually they do mainly chevys. I know because I build alot of engines..

[badf250]

do they specialize in 351W's, or are their machines programmed to handle other blocks? Not that I can afford it now, just curious.

As far as I know, They can work on just about anything. I know we sent a chevy 2.8 V6 ther to be rebiuilt, and have had a couple chrysler heads done there.