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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-

306 Turbo Or 357

  • Thread starter Thread starter Xterminator03
  • Start date Start date Jun 4, 2017
  • Tags Tags
    306 351w holley systemax turbo

306 turbo or 357 N/A

  • 306 Turbo

    Votes: 4 80.0%
  • 357 N/A

    Votes: 1 20.0%

  • Total voters
    5

Xterminator03

Member
Sep 23, 2004
157
0
16
NEW YORK
Jun 4, 2017
#1
  • Jun 4, 2017
  • #1
I am undecided. I currently have a 306 where I'm having some issues with. ( Oil and gas leaking from throttle body onto valve cover). So I will be pulling out the engine and rebuilding the motor. At that time I would like to go Turbo with an on3 performance kit 66mm. Or there is a new 351 bored .30 that just came out of the machine shop. That is beign offered to me for $1500.00. My question should I spend the money on the 306 turbo or the 357 N/A.

My current set up that I will be re using for the 306 turbo or for the 357

Holley systemax II top end kit. ( Will change he can for both turbo or 351) (will need to change intake for 351)
Bbk shorty headers
24lbs injector (will replace with 60 if turbo)
Aeromotive fuel rail
Jegs distributor (will replace if I go 351)
75mm throttle body

Will the Holley heads work work well with the 351 setup?

I am trying to get this done for around $2,500.00.
The 357 short block will cost me $1500.00
The on3 turbo will cost $1900.00

What do you think I should do.
 

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
27,872
10,543
203
polk county florida
Jun 9, 2017
#2
  • Jun 9, 2017
  • #2
351 na
 
Reactions: RangerJoe
P

Purdytang9

Active User
Apr 12, 2017
54
5
18
Jun 14, 2017
#3
  • Jun 14, 2017
  • #3
Hard to beat the feeling of boost...its addicting...
 
Reactions: General karthief

General karthief

wonder how much it would cost to ship you a pair
5 Year Member
Aug 25, 2016
27,872
10,543
203
polk county florida
Jun 14, 2017
#4
  • Jun 14, 2017
  • #4
Ok, 351 turbo
Fixt
 
Reactions: Mstng93SSP, Davedacarpainter and a91what

a91what

SendMeUrDataLog
10 Year Member
Apr 6, 2011
10,739
6,720
214
Hillsborough county
Jun 14, 2017
#5
  • Jun 14, 2017
  • #5
I can't get past the first part.....

How do oil and gas get into the throttle body??? Neither one goes through around or into it.
 
Reactions: A5literMan and hoopty5.0

NIKwoaC

中國製造
15 Year Member
Oct 31, 2006
5,525
943
214
Chengdu Province
Jun 15, 2017
#6
  • Jun 15, 2017
  • #6
a91what said:
I can't get past the first part.....

How do oil and gas get into the throttle body??? Neither one goes through around or into it.
Click to expand...

It's been a while for me, since my 90mm TB doesn't have stock-location ports, but don't the 75mm and smaller TBs have a vent line from the passenger side valve cover? That could explain the oil.

But gas, yea, no reason there should be gas up there.
 

hoopty5.0

mechanicus terribilis
15 Year Member
Dec 14, 2010
7,778
6,933
214
SW Houston
Jun 15, 2017
#7
  • Jun 15, 2017
  • #7
The 351 is not in your budget of $2500. That should narrow it down for you. Do you have headers? Flywheel? Balancer? Intake? That's a lot of money.
 

A5literMan

At least it is lumpy...
5 Year Member
Jul 30, 2011
4,674
2,343
194
Illinois
Jun 15, 2017
#8
  • Jun 15, 2017
  • #8
1500$ for a complete shortblock? That includes pistons,rods,crank,rings,bearings and balancer-flywheel/flexplate? If so it's not a terrible price if quality parts were used. Fresh machined block alone usually brings about a 500$ price tag around here.

As far as your budget...you need a bigger one in either case imo. The Holley heads are very restricted compared to almost all aftermarket options. They are fine for a mild 306 with some boost but for a n/a 357...bleh. Also the on3 kits are known to be hit or miss on quality and you need more parts to complete.
 
Reactions: General karthief

RangerJoe

I leave the horn on while driving
15 Year Member
Apr 26, 2010
2,560
1,146
184
Georgia
Jun 15, 2017
#9
  • Jun 15, 2017
  • #9
hoopty5.0 said:
The 351 is not in your budget of $2500. That should narrow it down for you. Do you have headers? Flywheel? Balancer? Intake? That's a lot of money.
Click to expand...

I don't think a rebuilt, turbo 302 fits either. Maybe a well warmed over 306 for that budget.

Joe
 
Reactions: A5literMan

FoxMustangLvr

I love my Pimp
SN Certified Technician
Oct 14, 2012
4,968
3,514
204
Spokane, Wa
Jun 15, 2017
#10
  • Jun 15, 2017
  • #10
$2,500 won't even get you an HCI combo that's worth the time and investment. Is there a carb involved? If not a megasquirt system with wideband will run a person $700+ alone. There are so many consumables and small pieces that really add to a build that nobody even bothers reporting but I bet @hoopty5.0 @a91what and myself have a stack of receipts that amount to a small fortune in short trips to True Value hardware or a parts store for odds and ends that pester your wallet.
 
Reactions: hoopty5.0, General karthief, RangerJoe and 1 other person

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
6,945
5,816
213
Jun 15, 2017
#11
  • Jun 15, 2017
  • #11
NIKwoaC said:
It's been a while for me, since my 90mm TB doesn't have stock-location ports, but don't the 75mm and smaller TBs have a vent line from the passenger side valve cover? That could explain the oil.

But gas, yea, no reason there should be gas up there.
Click to expand...

I'm thinking its gas mixed with oil caused by over pressurization of the crankcase, caused by blow by, caused by worn rings or cylinder walls, caused by hard driving, low maintenance, or high mileage.

Or....it could be caused by a clogged pcv screen in the lower intake....or all of the above.
 

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
6,945
5,816
213
Jun 15, 2017
#12
  • Jun 15, 2017
  • #12
I've got well over $2500 in my on3 kit and supporting mods. I'm scared to add it all up or list them...so please don't ask
 
Reactions: FoxMustangLvr

FoxMustangLvr

I love my Pimp
SN Certified Technician
Oct 14, 2012
4,968
3,514
204
Spokane, Wa
Jun 15, 2017
#13
  • Jun 15, 2017
  • #13
90sickfox said:
I've got well over $2500 in my on3 kit and supporting mods. I'm scared to add it all up or list them...so please don't ask
Click to expand...
All I know is how much I bought the car for, from there it's just a blurr of $100 bills that would make me have a heart attack if I added it all up. Where's my beer?
 
Reactions: A5literMan and General karthief

FoxMustangLvr

I love my Pimp
SN Certified Technician
Oct 14, 2012
4,968
3,514
204
Spokane, Wa
Jun 15, 2017
#14
  • Jun 15, 2017
  • #14
90sickfox said:
I've got well over $2500 in my on3 kit and supporting mods. I'm scared to add it all up or list them...so please don't ask
Click to expand...
Hey Scott, is your car running and driving yet? I need to catch up on your thread
 

90sickfox

Wasn't a pretty sight...and I've got big hands
SN Certified Technician
Mar 2, 2015
6,945
5,816
213
Jun 15, 2017
#15
  • Jun 15, 2017
  • #15
FoxMustangLvr said:
Hey Scott, is your car running and driving yet? I need to catch up on your thread
Click to expand...

It does run and could drive....just tightening up loose ends. Just got an oil catch can...and still have to finish grafting the front lower bumper.
 
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