MG Sports Cars

I've had 3 different versions of a SBF in my car, 200hp, 300hp, and now 400hp/378lbs with the 331 stroker. I have no special suspension or brake upgrades, in fact I'd call it a ratrod compared to 99% of you guys! Except Carl of course. The car seems to handle it just fine and the torque is great, but I think 300hp is a good number to shoot for, especially if getting decent fuel mileage is a concern.

I like torque more than power in a V8. I have the usual Ford V8 (maybe 280 ft/lbs at the wheels and a fairly flat curve). It is fun to get strong acceleration from 1500 rpm in any gear and I do enjoy running it up to 6,000 rpm - the power peak is at about 5,800 rpm. Starting from rest in third is easy as well. I have been considering stroking the engiune to 331, the only advantage being even stronger acceleration in the higher gears, especially 5th. But in terms of starting fron rest and accelerating through the gears, the limitation now is traction, so a 331 would not improve things (except possibly on a drag strip with a stickier surface). But it would improve real world acceleration for times when I am too lazy to down shift. That brings up the interesting concept of using a modern 5 or 6 speed automatic with the "300 hp engine". Such a transmission has many gear ratios to choose from and down shifts every time. The instantly available torque multiplication from a lower gear ratio (or two) would go a long way towards filling the gap between a 300 hp engine and 400 hp engine by keeping the torque at the wheels near the traction limit more of the time with the smaller engine. This would be especially true with a "300 hp engine" like mine with a relatively flat torque curve between 2000 and 6000 rpm.

Larry, Good post. That is what I plan to do with the AW4 Jeep tranny(A340 Toyota)but mine is only 4 speeds, manual solenoid shift,OD 4th,narrower than GM. Jim Blackwood's is a bit wilder, with the 8 speed Lexus tranny. I plan on 300-400 HP which I think will be just right. Jim Blackwood is being pretty conservative in his 300+ HP estimate. I think the dyno numbers will be more like 450+ and give the Roadmaster a run for the money.



Edited 2 time(s). Last edit at 05/24/2010 01:46AM by mgb260.

When are one of you going to make an AWD MGB V8 similar to Stuart's Midget?
[gallery.brit-cars.com]



Edited 1 time(s). Last edit at 05/24/2010 10:17AM by trevorwj.

Trevor, I wouldn't count on it anytime soon, Sierra 4WD units are a bit scarce on this side of the pond and I haven't run across anything else that looks like it would fit a Spridget. (Yes, I've looked, the temptation was just too great after seeing Stuart's car)

Until Stuart submits a How It Was Done article, I'm not sure I believe his Midget even exists.

AWD has advantages... but certainly not for every car and application. You might for example recall that some constructors worked quite hard to put AWD on Formula One cars, and it was an extremely costly mistake. What would it really do for a MG except add a lot of cost, complexity, weight (much of it unsprung), and rotating mass?

Here in Colorado, when I explore unfamiliar mountain roads it's not uncommon to have a twisty and smooth paved road suddenly turn into a gravel road. AWD might be nice on those occasions...

"Here in Colorado, when I explore unfamiliar mountain roads it's not uncommon to have a twisty and smooth paved road suddenly turn into a gravel road. AWD might be nice on those occasions..."

I sure know what you mean about those roads out there. I took a trip one weekend around Beulah and somehow wound up in the San Isabel National Forest. On the other side of the mountain was 16in of snow and ice on a dirt road. I was sure glad I had my superduty and 4wd then. Best road trip I ever had. If I get another job out that way I might buy a house out there. Colorado is the most beautiful place in the world in my opinion.

This is a wonderful thread. I have two questions.

1. At 300hp and beyond, and assuming a rust-free shell, wouldn't shell reinforcement become part of the equation?

2. With 300hp as a target, what would you suggest should be specified in a reman 302 engine without aluminum heads initially?

1978 MGB, chrome bumper conversion,rolling painted shell (Merc Brilliant Silver)

The MGB body shell is generally considered to be satisfactory at the 300 hp level, especially the chrome bumper models. On rubber bumper models it can be considered worthwhile to add a reinforcemet from the foward spring hangers to the cross member just foward of it. Some also add reinforcement on the left side to compensate for the absence of a battery box there (chrome bumper cars have two battery boxes, rubber bumper cars just one box). It is also wise to consider the effect of body modificatons such as plastic fenders and excessively large holes for through the fender headers. But I am sure others have different opinions on this subject.

It is always best to use a roller cam 302 block as the roller cams offer more performance at low modification levels than flat tappet cams. Essentially, roller cams generaly open and close the valves faster so there is more time at higher lifts without excessive overlap and duration. It is also a good idea to go with through the fender headers from the start as the freer flow makes higher power outputs easier.With these factors taken into account, any stock block Ford 302 will be able to make 300 hp at the flywheel with just a head upgrade (even keeping the stock cam). Heads are the main limitation on a Ford 302 in that the flow is limited, especially at high lifts. Thus, adding a high lift cam or high ratio rockers gives little benefit with stock heads. But with aftermarket heads that show flow increases up to 0.6 inch lift (or even more) cam upgrades can make a big difference. But stock cams in Mustangs are not bad, and with high lift rockers (1.7 ratio) and aluminum heads can give over 350 hp at the flywheel. If you want to upgarde the cam now, before adding aluminum heads, be aware that the stock valve springs cannot tolerate high lifts and it is probably best to wait untl aluminum heads are added to consider a cam upgrade. With all stock heads and most aftermarket heads, exhaust flow suffers in comparison to intake flow. Also, the header situation in MGBs hurts exhaust flow, so I prefer dual pattern cams that have more exhaust duration than intake duration. Kelly Stevenson has such a cam (a Comp Cams XE 266 HR) and he had the highest output of any 302 at the dyo session last year.

For induction, hood clearance is limiting. All that can fit without a scoop is an Edlebrock performer (not a performer RPM). This will still easily support 350 hp at the flywheel (with the right heads) but there is no use planning on using a high rpm cam or overly large carburetor with it. Therefore, this manifold with a 575 to 625 cfm vac seconbdary carb will be satisfactory for both an iron head 302 and an upgraded aluminum head 302 with just some jetting changes. You can also use the Ford fuel injection system (most likely with hood modifications) like Kelly used and this will work with both the stock and improved engine. That is, the later injection systems (with mass flow?) can be used on most modified engines without retuning, but the earlier systems are not so adaptable.

As a disclamer, my experience with engine tuning is limited and you might want to get further advice.

RE: For induction, hood clearance is limiting. All that can fit without a scoop is an Edlebrock performer (not a performer RPM).

Larry knows way more than me but the above depends on where you put the motor. I'm using the fastcars IFS with ford mounts -- sets the motor back (far enough that clipping the corners of the firewall by the heater shelf is required) & low. I'm waiting on my 1 1/2" drop base to arrive but if my measurements are right using a 2" filter it'll clear the stock hood with no bulge and my Performer RPM air gap (clone). Base should be here by early next week; will know for sure then.

Rob is correct!

Engine placement can make a difference, farther back is good for hood clearance, and my engine is about one inch further foward than most Ford V8 installations (and probably several inches more foward than Rob's). When lowering the engine, be sure to lower the transmission mount to keep the driveshaft yoke angle correct, or adjust the rear axle angle as necessary.

One fairly obscure point is that the aluminum hoods give less clearance than the steel hoods. Apparently, the steel hoods came out with the factory V8s and were designed for extra clearance, even though most cars using them were not V8 powered.